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Full text of "Electric Welding"

ELECTRIC WELDING 



ELECTRIC WELDING 



BY 

ETHAN VIALL 

EDITOR AMERICAN MACHINIST 

Member American Society of Mechanical Engineers, Society of Automotive Engineers, 

American Institute of Electrical Engineers, Franklin Institute, American Welding 

Society. Author of Manufacture of Artillery Ammunition, United States 

Artillery Ammunition, United States Rifles and Machine Guns, 

Broaches and Broaching, Gas-Torch and Thermit Welding. 



FIRST EDITION 
THIRD IMPRESSION 



McGRAW-HILL BOOK COMPANY, INC. 

NEW YORK: 370 SEVENTH AVENUE" 

LONDON: 6 & 8 BOUVERIE ST., E. C. 4 

1921 



COPYRIGHT, 1921, BY THE 
McGRAW-HILL BOOK COMPANY, INC. 



PRINTED IN THE UNITED STATES OF AMERICA 



PREFACE 

Few fields afford a greater opportunity for study to the 
mechanic, the student, or the engineer, than that of electric 
welding. Arc welding, with its practical, every-day, shop appli- 
cations for repair and manufacture, is in some respects crowding 
closely into the field in which the gas-torch has seemed supreme. 
With the development of mechanical devices for the control of 
the arc, the range of application to production work has greatly 
increased. 

Resistance welding presents in its various branches some of 
the most interesting scientific and mechanical problems to be 
found anywhere. Spot-welding butt-welding line-welding 
all occupy a particular place in our manufacturing plants today, 
and new uses are being constantly found. 

In the gathering and arranging of the material used in this 
book, particular care has been taken to classify and place various 
subjects together as far as possible. This is not only convenient 
for reference purposes, but enables the reader to easily compare 
different makes and types of apparatus. In most cases, the 
name of the maker of each piece of apparatus is mentioned 
in the description in order to save the time of those seeking 
information. 

No time or pains have been spared in the endeavor to make 
this the most comprehensive book on electric welding equipment 
and practice, ever published. Every possible source of informa- 
tion known to the long-experienced editor has been drawn upon 
and properly credited. 

It is hoped that this book will prove a permanent record of 
electric welding as it is today, and also be an inspiration and 
source of information for those engaged in practice, research 
or development. 

ETHAN VIALL. 

New York City, 
November, 1920. 



3 



CM 

5 v 

o 



CONTENTS 



PAGE 

PREFACE v 

CHAPTER I 

ELECTRIC WELDING HISTORICAL 1- 8 

The Two Classes of Electric Welding The Zerner, the Ber- 
nardos, the Slavianoff, the Strohmenger-Slaughter and the 
LaGrange-Hoho Processes Early Methods of Connecting for 
Arc Welding Early Resistance Welding Apparatus First 
Practical Butt-Welding Device DeBcnardo Spot-Welds The 
Kleinschmidt Apparatus Bouchayer's Machine Principle of 
the Harmatta Patent The Taylor Cross-Current Spot-Welding 
Method. 

CHAPTER II 

ARC WELDING EQUIPMENT 9- 27 

What Electric Arc-Welding Is^ Uses of B.C. and A.C. 
Schematic Layout for an Arc- Welding Outfit Carbon Electrode 
Process Metallic Electrode Process Selection of Electrodes 
Relation of Approximate Arc Currents and Electrode Diam- 
eters Approximate Current Values for Plates of Different 
Thickness Illustrations of the Difference Between the Carbon 
and the Metallic Arc Methods Electrode Holders Sizes of 
Cable for Current Face Masks Selecting a Welding Outfit 
Eye Protection in Iron Welding Operations The Dangerous 
Rays Properties of Various Kinds of Glass. 

CHAPTER III 

DIFFERENT MAKES OF ARC WELDING SETS 28- 46 

General Electric Compound- Wound Balancer-Type Arc Weld- 
ing Set The Welding Control Panel Connections for G.E. 
Welding Set Data for Metallic-Electrode Arc Butt- and Lap- 
Welds Carbon-Electrode Cutting Speeds The Wilson Plastic- 
Arc Set Panel for Wilson Welding and Cutting Set Wilson- 
Portable Outfit The Lincoln Outfit Westinghouse Single- 



viii CONTENTS 

PAGE 

Operator Outfit The U.S. Outfit The "Zeus" Outfit The 
Arcwell Outfit Alternating-Current Are- Welding Apparatus 
G.E. Lead Burning Transformer. 

CHAPTER IV 

TRAINING ARC WELDERS 47- 65 

Use of Helmets and Shields The Welding Booth Welding 
Systems The Electrode Holder Arc Manipulation Arc 
Formation Fusion of Electrodes Maintenance of Arc 
Control of Arc Travel Weaving Arc and Fusion Character- 
istics Polarity Length of Arc Stability Overlap and 
Penetration Heat Conductivity and Capacity Expansion and 
Contraction of Parent Metal Contraction of Deposited 
Metal Welding Procedure Electrode Current Density In- 
spection Terminology. 

CHAPTER V 
CARBON-ELECTRODE ARC WELDING AND CUTTING 66- 80 

Currents Used with Carbon Arc Carbon and Graphite Elec- 
trodes Shapes and Size of Electrodes Filler Material 
Proper Welding Position Arc Manipulation Characteristics 
of the Arc Polarity Arc Length Building up Surfaces 
Fused Ends of Filler Rods Flanged Seam Welding Weld- 
ing Non-Ferrous Metals Applications of Carbon-Arc Weld- 
ing Cutting Data on Cutting Steel Plates Cutting Cast- 
iron Plates Cutting Cast-Iron Blocks. 

CHAPTER VI 
ARC WELDING PROCEDURE 81-108 

Resume of Welding Instructions Filling Sequence Welding 
Two Plates The Back-Step Method Welding a Square 
Patch Quasi-Arc Welding Typical Examples of Arc Weld- 
ing Examples of Tube Work Locomotive Work Welding 
Calculations Strength of Welds Stresses in Joints Inspec- 
tion of Metallic- Electrode Are- Welds Good and Bad Welds 
Electrode Diameters for Steel Plate Variation in Weld 
Strength with Change in Arc Current Effects of Short and 
Long Arcs Heat Treatment Effects of the Chemical Com- 
position of Electrodes Physical Characteristics of Plates 
Chemical Analysis of Specimens The Welding Committees 
Electrodes. 



CHAPTER VII 

PAGE 

ARC WELDING TERMS AND SYMBOLS 109-126 

Definitions of Strap, Butt, Lap, Fillet, Plug and Tee Welds 
The Single V, Double V, Straight, Single Bevel, Double Bevel, 
Flat, Horizontal, Vertical and Overhead Weld Tack, Caulking, 
Strength, Composite, Reinforced, Flush and Concave Welds 
Symbols for Various Kinds of Welds. 

CHAPTER VIII 

EXAMPLES OF ARC-WELDING JOBS 127-170 

Work on the German Ships Seventy Cylinders Saved Without 
Replacement The' Broken Cylinders of the George Washing- 
ton Cylinders of the Pocaliontas General Ship Work 
Locomotive Work Repair on a Locomotive Frame Built-Up 
Pedestal Jaw Repaired Drive Wheel Flue and Firebox 
Work Side Frames and Couplers Amount Saved by Weld- 
ing Training of Welders Welded Rails and Cross-Overs 
Built-Up Rolling Mill Pods Repaired Mill Housing Welded 
Blow-Holes in Pulley Method of Removing Broken Taps 
Electric Car Equipment Maintenance A Large Crankshaft 
Repair Welding High-Speed Tips onto Mild Steel Shanks 
An All-Welded Mill Building Speed of Arc Welding. 

CHAPTER IX 

PHYSICAL PROPERTIES OF ARC-FUSED STEEL '. 171-190 

Preliminary Examinations of Arc Welds Method of Prepar- 
ing Test Specimens Arrangement of the Welding Apparatus 
The l * Paste ' ' Used for Coated Electrodes Composition of Elec- 
trodes Before and After Fusing Relation Between Nitrogen- 
Content and Current Density Appearance of Specimens After 
Test Tensile Properties of Electrodes Results of Tests on 
Fifty Specimens Mechanical Properties of the Arc-Fused 
Metal Dependence of Physical Properties on Soundness 
Macrostructure Discussion of the Results of the Tests Com- 
parison of the Bureau of Standards and the Wirt-Jones Tests. 

CHAPTER X 

METALLOGRAPHY OF ARC-FUSED STEEL 191-213 

General Features of the Microstructure of the Electrodes 
Used Microscopic Evidence of Unsonndness Characteristic 
"Needles" or "Plates 77 Plates Probably due to Nitrates 



CONTENTS 



Relation of Microstructure to the Path of Rupture Effect of 
Heat Treatment Upon Structure Persistence of " Plates" 
After Annealing Thermal Analysis of Arc-Fused Steel 
Summary. 

CHAPTER XI 

AUTOMATIC ARC WELDING ..................................... 214-238 

The General Electric Automatic Arc Welding Machine The 
Welding Head Set-Up for Circular Welding Set-Up for 
Building Up a Shaft Diagram of Control of Feed Motor 
Some Work Done by the Machine Repaired Crane Wheels 
Welded Hub Stampings Welded Rear Axle Housings Welded 
Tank Seam The Morton Semi- Automatic Machine Methods 
of Mechanically Stabilizing and Controlling the Arc Examples 
of Work Done by the Morton Machine The G.E. Electric- Arc 
Seam Welding Machine. 

CHAPTER XII 

BUTT-WELDING MACHINES AND WORK .......................... 239-275 

Resistance Welding Machines Butt-Welding Machines Cur- 
rent Used in Butt-Welding How the Secondary Windings of 
the Transformer are Connected Typical Butt-Welding Ma- 
chine with Main Parts Named How the Clamping Jaws are 
Operated Annealing Welds Portable Wire Welding Ma- 
chines Examples of Butt- Welding Jobs Welding Copper and 
Brass .Rod Welding Aluminum Typical Copper Welds 
T-Welding Welding Band Saws Automobile Rim Welding 
The " Flash- Weld ' ' Welding Heavy Truck Rims Welding 
Pipe The Type of Clamp Used for Pipe The Approximate 
Current Used for Pipe Welding The Winfield Butt -Welding 
Machines Cost of Butt-Welds The Federal Butt-Welding 
Machines Welding Motor Bars to the End Rings Welding 
Valve Elbows on Liberty Motor Cylinders An Automatic 
Chain-Making Machine Electro-Percussive Welding How the 
Machine is Made Uses of Percussive Welding Power Con- 

sumed and Time to Make a Percussive Weld. 



CHAPTER XIII 

SPOT- WELDING MACHINES AND WORK ........... . ............... 276-323 

Spot- Welding Three Desirable Welding Conditions Welding 
Galvanized Iron and Other Metals Mash Welding Details of 
Standard Spot-Welding Machines Foot-, Automatic-, and 



. CONTENTS xi 

PAGE 

Hand-Operated Machines Examples of Spot-Welding Work 
Form and Sizes of Die-Points for Spot- Welding The Win- 
field Spot-Welding Machines Machine for Welding Auto- 
mobile Bodies The Federal Spot- Welding Machines The 
Federal Water-Cooled Die-Points Botatable Head Two-Spot 
Welding Machine Automatic Machine for Welding Channels 
Automatic Pulley Welding Machine The Taylor Cross-Cur- 
rent, Spot-Welding Machines Automatic Hog-Ring Machine 
A Space-Block Welding Machine Combination Spot- and 
Line-Welding Machines Spot-Welding Machines for Ship 
Work A Large Portable Spot-Welding Machine Duplex 
Welding Machine A Powerful Experimental Machine 
Portable Mash-Welding Machine for Square or Round Eods 
Cost of Spot Welding. 

CHAPTER XIV 

WELDING BOILER TUBES BY THE ELECTRIC RESISTANCE PROCESS . 324-342 

How Boiler Flues are Held for Welding How the Tube 
Ends are Prepared Scarf- Weld Straight Butt-WeldFlash 
Weld Use of a Flux How the Work is Placed in the Jaws 
to Heat Evenly Electric and Oil Heating Compared Kind 
of Machine to Use Flash Welding Welding in the Topeka 
Shops of the Santa Fe Railroad The Way the Work Heats 
Up The Final Rolling. 

CHAPTER XV 

ELECTRIC WELDING OF HIGH-SPEED STEEL AND STELLTTE IN TOOL 
MANUFACTURE 343-364 

The Machines Used to Weld Tools Welding High-Speed to 
Low-Carbon Steel Examples of Welded Tools Jaws for 
Special Work How the Parts are Arranged for Welding 
Clamping in the Jaws Insert Welding Jaws for Stellite 
Welding Jaws for Stellite Insert Welding The Vertical Type 
of Welding Machine Making a "Mash- Weld" Jaws for 
Mash-Welding Grooving the Pieces to be Welded Current 
Consumption for Various Jobs Sizes of Wire to Use. 

CHAPTER XVI 

ELECTRIC SEAM WELDING , . . . 365-381 

The Process of Seam Welding Kind of Machine Used De- 
tails of the Roller Head Thomson Lap-Seam Welding Ma- 
chine Welding Oil Stove Burner Tubes Jig for Welding 



xii CONTENTS 

PAGE 

Automobile Muffler Tubes Jig for Welding Large Can 
Seams Jig for Welding Bucket Bodies Jig for Welding 
Ends of Metal Strips Together Flange Seam Welding Jig 
for Welding Teapot Spouts Approximate Current for Six- 
Inch Seam for Various Thicknesses of Sheet Metal Size of 
Wire to Use in Connecting up a Welding Machine. 

CHAPTER XVII 

MAKING PROPER BATES FOR ELECTRIC WELDING, AND THE STRENGTH 
OF WELDS 382-399 

Reasons for Misunderstanding Between User and Producer- 
The Metering Proposition Energy Consumption of Resistance 
Welding for Commercial Grades of Sheet Iron Effect of 
Clamping Distance Between Electrodes Upon Time and Energy 
Demand The Load Factor Maximum Demand Power 
Factor Strength of Combination Spot and Arc Welds Spot 
Welding Tests on Hoop Iron Strength of Spot- Welded 
Holes Plates Plugged by Welding Tested Plates Tensile 
Tests of Plates Plugged by Spot-Welding Strength of Mash- 
Welded Rods Strength of Resistance Butt- Welds Elementary 
Electric Information What is a Volt? What is an Ampere? 
What is a Kilowatt ? What is Kva? 



ELECTRIC WELDING 



CHAPTER I 
ELECTRIC WELDING HISTORICAL 

All electric welding may be divided into two general classes 
arc welding and resistance welding. In each class there are 
a number of ways of obtaining the desired results. Arc welding 
is the older process, and appears to have been first used by de 
Meritens in 1881 for uniting parts of storage batteries. He 
connected the work to the positive pole of a current supply 
capable of maintaining an arc. The other pole was connected 
to a carbon rod. An arc was struck by touching the carbon 
rod to the work and withdrawing it slightly. The heat generated 
fused the metal parts together, the arc being applied in a way 
similar to that of the flame of the modern gas torch. 

Of the several methods of arc welding, there are the Zerner, 
the Bernardos, the 'Slavianoff and the Strohmeiiger-Slaughter 
processes, as well as some modifications of them. The different 
methods are named after the men generally credited with being 
responsible for their development. The LaGrange-Hoho process 
is not a welding process at all, as it is merely a method of heating 
metal which is then welded by hammering, as in blacksmith 
work. It is sometimes called the "water-pail forge." 

The Zerner process employs two carbon rods fastened in a 
holder so that their ends converge like a V, as shown in Fig. 1. 
An arc is drawn between the converging .ends and this arc is 
caused to impinge on the work by means of a powerful electro- 
magnet. The flame acts in such a manner that this process is 
commonly known as the electric blowpipe method. The Zerner 
process is so complicated and requires so much skill that it is 
practically useless. A modification of the Zerner process, known 



2 ELECTRIC WELDING 

as the "voltex process/' uses carbon rods containing a small 
percentage of metallic oxide which is converted into metallic 
vapor. This vapor increases the size of the arc and to some 
extent prevents the excessive carbonizing of the work. This 
process, however, is about as impractical for general use as the 
other. 

The Bernardos process employs a single carboii or graphite 




FiG. 1 The Zerner Electric "Blow-Pipe." 

rod and the arc is drawn between this rod and the work. A 
sketch of the original apparatus is shown in Fig. 2. This 
is commonly called the carbon-electrode process. In using this 
method it is considered advisable to connect the carbon to the 
negative side and the work to the positive. This prevents the 
carbon of the rod from being carried into the metal and a softer 
weld is produced. 

In the Slavianoff process a metal electrode is used instead 



ELECTRIC WELDINGHISTORICAL 3 

of a carbon. This process is known as the metallic-electrode 
process. 

The Strohmenger-Slaughtcr, or covered electrode, process 
is similar to the Slavianoff except that a coated metallic elec- 




Fi<3. 2. -Original Bornanlos ( 'urhnn Klortrodr Apparatus. 



end 
Rheostat 




Circuit. 
Breaker, 



i'lG. 3. Arc Welding Circuits as Pirnt Used, 



trode is used. In this process either dirool or alternating cur- 
rent may he used. 

Some of the early methods of connect ing up For arc welding 
are shown in Fi^. ;]. 

The LaQ range- Hoho heating process makes use of a wooden 
tank tilled with some electrolyte, such as a solution of sodium 



ELECTRIC WELDING 



or potassium carbonate. A plate connected to the positive wire 
is immersed in the liquid and the work to be heated is connected 
to the negative wire. The work is then immersed in the liquid. 
When the piece has reached a welding temperature it is removed 
and the weld performed by means of a hammer and anvil 

Resistance Welding. The idea of joining metals by means 
of an electric current, known as the resistance or incandescent 
process, was conceived by Elihu Thomson some time in 1877. 




M^ 



FIG. 4. First Practical Electric Butt Welding Device, Patented 
by Elihu Thomson, Aug. 10, 1886. 

Little was done with the idea from a practical standpoint for 
several years. Between 1883 and 1885 he developed and built 
an experimental machine. A larger machine was built in 1886. 
He obtained his first patent on a device for electric welding 
Aug. 10, 1886. The general outline of this first device is shown 
in Fig. 4. The first experiments were mostly confined to what 
is now known as butt welding, and it was soon found that the 
jaws used to hold the parts heated excessively. To remedy this 
water-cooled clamping jaws were developed. 



ELECTRIC WELDING HISTORICAL 




FIG. 5. Platos ''Spot Welded" by Carbon Arc. 




CK (5, The DeBeimrdo Carbon KH<Htro<lo Hpot \\Vlding Apparatus. 




. The KhlnH<hnii*lt Apparatus Ut-?mg (!opptr H 



6 ELECTRIC WELDING 

Closely following the butt welding came other applications 
of the resistance process, such as spot, point or projection, ridge 
and seam welding. Percussive welding, which is a form of 
resistance welding, was developed about 1905. Since spot weld- 
ing is such an important factor in the manufacturing field today 




FIG. 8. Bonchayer's Spot Welding Machine, Using Duplex Copper 

Electrodes. 

the evolution of this process, as indicated by the more prominent 
patents, will be of considerable interest : Pig 5 shows plates spot 
welded together by means of the carbon arc. This was patented 
by DeBenardo, May 17, 1887, Pat. No. 363,320. The claims 
cover a weld made at points only. The darkened places indicate 



ELECTRIC WELDINGHISTORICAL 7 

where the welds were made. Fig. 6 shows the apparatus made 
by DeBenardo for making "spot welds," as they are known 
today. He patented this in Germany, Jan. 21, 1888. Carbon 
electrodes were used. This patent was probably the first to 
cover the process of welding under pressure and also for passing 
the current through the sheets being welded. The German patent 
number was 46,776 49. 

The apparatus shown in Fig. 7 is known as the Kleinschmidt 
patent, No. 616,463, issued Dec. 20, 1898. The patent claims 
cover the first use of pointed copper electrodes and raised sec- 
tions, or projections, on the work in order to localize the flow 
of the current at the point where the weld was to be effected. 



T7 



J\. 



FIG. 9. Principle of the Harmatta Process, Using Copper JSlcetrodes. 

Considerable pressure was also applied to the electrodes and 
work by mechanical means. 

Fig. 8 shows diagrammatically Bouehayer's spot welding 
machine, patented in France, March 13, 1903, No. 330,200. He 
used two transformers, one on each side of the work. Duplex 
copper electrodes were used, and if the transformers were con- 
nected parallel one spot weld would be made at each operation. 
If the transformers were connected in series two spot welds 
would be made. 

Fig. 9 illustrates the principle of the Harmatta patent, No. 
1,046,066, issued Dec. 3, 1912. This is practically the same as 
the DeBenardo patent, No. 46,776 49, except that copper elec- 



ELECTRIC WELDING 



trodes are used. However, it is under the Harmatta patent that 
a majority of the spot welding machines in use today are made. 
Fig. 10 illustrates the principle on which the Taylor patent 
is founded. This patent was issued Oct. 16, 1917, No. 1,243,004. 
It covers the use of two currents which are caused to cross the 
path of each other in a diagonal direction, concentrating the 
heating effects at the place of intersection. 




a 

X 


b 

y 



/ 

b 




\ 

Of 



FIG. 10. The Taylor Cross-Current Spot Welding Method. 

From the foregoing it will be seen that spot welds, as this 
term is now understood, can be produced in a number of ways, 
none of which methods are identical. As a matter of fact, spot 
welds can be produced by means of the gas torch or by the 
blacksmith forge and anvil, although these methods would not 
be economical. 



CHAPTER II 
ARC WELDING EQUIPMENT 

Electric Arc Welding is the transformation of electrical 
energy into heat through the medium of an arc for the purpose 
of melting and fusing together two metals, allowing them to 
melt, unite, and then cool. The fusion is accomplished entirely 
without pressure. The heat is produced by the passage of an 
electric current from OIK* conductor to another through air which 
is a poor conductor of elect r ie/ity, and offers a high resistance 
to its passage. The heat of the arc is the hottest flame that is 
obtainable, having a temperature estimated to be between 
3,500 and 4,000 deg. (1 (ti,W2 to 7,232 deg. P.). 

The metal to be welded is made one terminal of the circuit, 
the other terminal being the electrode. By bringing the elec- 
trode into contact with the metal and instantly withdrawing it 
a short distance, an arc- is established between the two. Through 
the medium of the heat thus produced, metal may be entirely 
melted away or cut, added to or built up, or fused to another 
piece of metal as desired. A particularly advantageous feature 
of the electric arc weld is afforded through the concentration 
of this intense heat in a small area, enabling it to be applied 
just where it is needed. 

Direct-current is now more generally used for arc welding 
t han alternating-current. 

When using direct-current, the metal to be welded is made 
the positive terminal of the circuit, and the electrode is made the 
negative terminal. 

Regarding alternating-current it is obvious that an equal 
amount of heat will be developed at the work and at the elec- 
trode, while with direct-current welding we have considerably 
more heat developed at the positive terminal. Also in are weld- 
ing the negative electrode determines the character of the are, 
which permits of making additions to the weld in a way that is 

9 



10 



ELECTRIC WELDING 



not possible with alternating-current. Inasmuch as the work 
always has considerably greater heat-absorbing capacity than the 
electrode, it would seem only reasonable that the direct-current 
arc is inherently better suited for this work. 

Two systems of electric arc welding, based on the type of 
electrode employed, are in general use, known as the carbon (or 
graphite) and the metallic electrode processes. The latter 




6rid 
'Resistors 



lectrode 



Courte&y of the Westinghowe Co. 
FiG. 11. Simple Schematic Welding Circuit. 

process is also sub-divided into those using the bare and the 
covered metallic electrodes. 

A simple schematic layout for an arc- wold ing outfit is shown 
in Fig. 11. 

The Carbon Electrode Process. Li this process, the nega- 
tive terminal or electrode is a carbon pencil from 6 to 12 in. 
in length and from | to 1| in. in diameter. This was the original 
process devised by Bernardos and has been in more or less general 



ARC WELDING EQUIPMENT 11 

use for more than thirty years. The metal is made the positive 
terminal as in the metallic electrode process in order that the 
greater heat developed in this terminal may be applied just 
where it is needed. Also, if the carbon were positive, the tendency 
would be for the carbon particles to flow into the weld and 
thereby make it hard and more difficult to machine. 

The current used in this process is usually between 300 and 
450 amp. For some special applications as high as from 600 
to 800 may be required, especially if considerable speed is desired. 
The arc supplies the heat and the filler metal 'must be fed into 
the weld by hand from a metallic bar. 

The class of work to which the carbon process may be applied 
includes cutting or melting of metals, repairing broken parts 
and building up materials, but it is not especially adapted to 
work where strength is of prime importance unless the operator 
is trained in the use of the carbon electrode. It is not practical 
to weld with it overhead or on a vertical surface but there are 
many classes of work which can be profitably done by this process. 
It can be used very advantageously for improving the finished 
surface of welds made by metal electrodes. The carbon electrode 
process is very often useful for cutting cast iron and non-ferrous 
metals, and for filling up blowholes. 

The Metallic Electrode Process. In the metallic electrode 
process, a metal rod or pencil is made the negative terminal, 
and the metal to be welded becomes the positive terminal. 

When the arc is drawn, the metal rod melts at the end and 
is automatically deposited in a molten state in the hottest portion 
of the weld surface. Since the filler is carried directly to the 
weld, this process is particularly well adapted to work on vertical 
surfaces and to overhead work. 

If the proper length of arc is uniformly maintained on clean 
work, the voltage across the arc will never greatly exceed 22 
volts for bare electrodes and 35 volts for coated electrodes. The 
arc length will vary to a certain degree however, owing to the 
physical impossibility of an operator being able to hold the elec- 
trode at an absolutely uniform distance from the metal through- 
out the time required to make the weld. 

It is very essential that the surfaces be absolutely clean and 
free from oxides and dirt, as any foreign matter present will 
materially affect the success of the weld. 



12 ELECTRIC WELDING 

"When using a metallic electrode, the arc wjiich is formed 
by withdrawing it from the work, consists of a highly luminous 
central core of iron vapor surrounded by a flame composed 
largely of oxide vapors. At the temperature prevailing in the 
arc stream and at the electrode terminals, chemical combinations 
occur instantaneously between the vaporized metals and the 
atmospheric gases. These reactions continue until a flame of 
incandescent gaseous compounds is formed which completely 
envelopes the arc core. However, drafts created by the high 
temperature of the vapors and by local air currents tend to 
remove this protecting screen as fast as it is formed, making it 
necessary for the welder to manipulate the electrode so that the 
maximum protective flame for both arc stream and electrode 
deposit is continuously secured. This can be obtained auto- 
matically by the maintenance of a short arc and the proper 
inclination of the electrode towards the work in order to com- 
pensate for draft currents. 

Selection of Electrodes. The use of a metallic electrode 
for arc welding has proved more satisfactory than the use of 
a carbon or graphite electrode which necessitates feeding the 
new metal or filler into the arc by means of a rod or wire. The 
chief reason for this is that, when the metallic electrode process 
is used, the end of the electrode is melted and the molten metal 
is carried through the arc to be deposited on the material being 
welded at the point where the material is in a molten state 
produced by the heat of the arc. Thus a perfect union or fusion 
is produced with the newly deposited metal. 

Wire for metallic arc welding must be of uniform, homogene- 
ous structure, free from segregation, oxides, pipes, seams, etc. 
The commercial weldability of electrodes should be determined 
by means of tests performed by an experienced operator, who 
can ascertain whether the wire flows smoothly and evenly through 
the arc without any detrimental phenomena. 

The following table indicates the maximum range of the 
chemical composition of bare electrodes for welding mild steel: 

Carbon trace up to 0.25% 

Manganese trace up to 0.99% 

Phosphorous not to exceed 0.05% 

Sulphur not to exceed 0.05% 

Silicon not to exceed 0.08% 



ARC WELDING EQUIPMENT 



13 



The composition of the mild steel electrodes, commonly used, 
is around 0.18 per cent carbon, and manganese not exceeding 
0.05 per cent, with only a trace of phosphorus, sulphur and 
silicon. 

The size, in diameter, ordinarily required will be 1 / 8 in., Vaa ' 
in., and 3 / lQ in. and only occasionally the 8 / 32 in. 

These electrodes are furnished by a number of firms, among 
whom are John A. Kocbling's Sons Co., Trenton, N. J.; American 
Rolling Mills Co., Middlctown, Ohio ; American Steel and Wire 




100 150 

Amperes Arc Current 



EDO 



250 



Courtesy of the Wedinghousc Co. 
PIG. 12. Relation of Approximate Arc Currents and Electrode Diameters. 

(Jo., Pittsburgh ; Ferridc Electric Welding Wire Co., New 
York City; Page Woven Wire Co., Monesson, Pa.; John Potts 
Co., Philadelphia. 

A coated electrode is one which has had a coating of some 
kind applied to its surface for the purpose of totally or partially 
excluding the atmosphere from the metal while in a molten state 
when passing through the arc and after it has been deposited. 

The proper size of electrode may be determined from Fig. 
12 from, which it will be seen that the class of work and current 
used are both factors determining the size of the electrode for 



14 ELECTRIC WELDING 

welding steel plates of various thicknesses. To find the diameter 
of the metallic electrode required, select, for example, a three- 
eighths plate, and follow horizontally to the "Thickness of the 
Plate Curve. 7 ' The vertical line through this intersection repre- 
sents about 110 amp. as the most suitable current to be used 
with this size of plate. Then follow this vertical line to its 
intersection with the "Diameter of Electrode" curve which 
locates a horizontal line representing approximately a:n electrode 
%o in. in diameter. In a similar manner, a 1 /.An. plate requires 
about 125 amp. and a r '/ 32 -in. electrode. 

The amount of current to be used is dependent on the thick- 
ness of the plate to be welded when this value is $ in. or less. 
Average values for welding mild steel plates with direct current 
are indicated by the curve referred to above in connection with 
the selection of the electrode of proper size. These data are also 
shown in Table I. 

TABLE I. APPROXIMATE CURRENT VALUES H>it PLATKS OF DIFFERENT 

THICKNESS 



Plate Thickness 


Current 


Electrode Diameter 


in Inches 


in Amperes 


in Inches 


1/16 


20 to 50 


1/16 


1/8 


50 to 85 


3/32 


3/16 


75 to 110 


1/8 


1/4 


90 to 125 


1/8 


3/8 


110 to 150 


5/32 


1/2 


125 to 170 


5/32 


5/8 


140 to 185 


5/32 


3/4 


150 to 200 


3/16 


7/8 


165 to 215 


'3/16 


1 


175 to 225 


3/16 



It should be borne in mind, however, that, these values are 
only approximate as the amount of current to be used is 
dependent on the temperature of the plate and also upon the 
type of joint. For example, when making a lap weld between 
two ~J-in. steel plates at ordinary air temperature of about 
65 deg. F. it has been found that the extra good results were 
obtained by using a current of about 225 amp. and a 8 / 16 -in. 
diameter electrode. . The explanation for the high current per- 
missible is the tremendous heat storage and dissipation capacity 
of the lapped plates which makes the combination practically 



AEG WELDING EQUIPMENT 



15 




FIG. 13. Carbon-Arc Welding, "Using King Mask. 




FIG. 14. Metallic-Arc Welding, Using a Hand Shield. 



16 



ELECTRIC WELDING 



equivalent to that of a butt weld of two 1-in. plates. For that 
reason the above values will be very greatly increased in the 
case of lap welds which require practically twice the amount 
of current taken by the butt welds. 

When the proper current value is used there will be a crater, 




FlG. 15. Simple Form of Electrode Holder. 

or depression, formed when the arc is interrupted. This shows 
that the newly deposited metal is penetrating or "biting into" 
the work. 

The difference between the carbon and the metallic electrode 
processes can be seen in Figs. 13 and 14. In Fig. 13 the welder 




FIG. 16. Special Make of Electrode Holder. 

is using a carbon electrode and feeding metal into the weld from 
a metal rod held in his left hand. In Fig. 14 the metal rod 
is held in a special holder and not only carries the current but 
metal from it is deposited on the work. 

Electrode holders should be simple, mechanically strong, and 
so designed as to hold the electrode firmly. It should be prac- 



ARC WELDING EQUIPMENT 



17 



tically impossible to burn or damage the holder by accidental 
contact so that it will not work. Small, flimsy or light projecting 
parts are almost sure to be broken off or bent. Fig. 15 shows 
one of these holders that answers the requirements. However, 
any of the companies selling arc welding apparatus will be able 
to supply dependable holders. 

A holder made by the Arc "Welding Machine Co., New York, 
is shown in Fig. 16 and in detail in Fig. 17. The metal rod 
is clamped in by means of an eccentric segment operated by 
a thumb lever. If the rod should freeze to the work it will not 
pull out of the holder, but will be gripped all the tighter. The 




FIG. 17. Details of Special Electrode Holder. 

welding current enters at the rear end of the composition shank, 
passes along the shank to the head of the tool, and from there 
directly into the electrode. It will be noted that there are no 
joints in this tool except where the cable is soldered into the 
shank. There is a relatively large contact surface between the 
electrode and the holding head, which precludes any possible 
heating at this point. The trigger is intended for remote control 
employed with the closed circuit system. Whenever this holder 
is used on other systems, the trigger is omitted. 

Cable. For arc welding service the cables leading to the 
electrode holder should be very flexible in order to allow the 
operator full control of the arc. 

The following sizes of cable have been found by the General 



18 



ELECTRIC WELDING 



Electric Co. suitable for this service, due account being taken 
of the intermittent character of the work. 

It is extra flexible stranded dynamo cable, insulated for 75-v. 
circuit, with varnished cambric insulation, covered with weather- 
proof braid. 

Circular Mills 
90,000 

150,000 
260,000 

It will be noted in Figs. 13 and 14, that two different ways 
of protecting the eyes are shown. One man has a helmet and 



Amperes 


JSize of Cable 


Up to 200 


225/24 


Over 200 
Up to 500 


375/24 


Over 500 
U.p to 1,000 


650/24 




FiG. 18. King Face Masks With and Without Side Screens. 

the other uses a shield held in the hand. Conditions under which 
the welders work, and their personal preferences, largely dictate 
which type is to be used. However, no welder should ever at- 
tempt are welding without a protecting screen, fitted with the 
right kind of glass. Cheap glass is dear at any price, for the 
light rays thrown off from the arc are very dangerous to the 
eyesight. The guard should be so made as to not only protect 
the eyes from, dangerous light rays, but should also protect the 
face and neck from flying sparks of metal. 

A very good face mask made by Julius King Optical Co., 
New York, is shown in Fig. 18. These masks are made of fiber 



ARC WELDING EQUIPMENT 



19 



and provision is made for a free circulation of air between the 
front and the face, not only keeping the operator cool, but 
preventing the tendency of the lenses to fog. The masks are 
supported by bands over the head and it is said that weight 




FIG. 19. King Hand Shields. 




Fie. 20. Method of Using Screens to Protect Others. 



is not apparent and that they are as comfortable to wear as a 
cap. Two styles are made with and without side screens. The 
one without screens may be had with combination lenses tinted 
for acetylene or electric welding or with any other tint for 
specific work. The one with side screens, providing side vision, 



20 



ELECTRIC WELDING 




1 



ARC WELDING EQUIPMENT 21 

is fitted either with combination lenses or with ciear Saniglass 
lenses. A hand shield is shown in Fig. 19. 

In arc welding in the open, other workmen or onlookers are 
liable to injury as well as the welders, so screens should be placed 
around the work to conceal the light rays from the view of 
others besides the welder. Such an arrangement is shown in 
Fig. 20. 

Where repetition work is to be done, it is well to provide 
individual stalls or booths, somewhat similar to the one shown 
in Fig. 21. These were designed for use in the welding schools 
under the supervision of the Lincoln Electric Co. For actual 
shop work, curtains or screens should be provided back of the 
welders. 

It must be remembered also, that owing to the presence of 
ultra-violet rays, severe flesh burns may result with some people 
if proper gloves and clothing are not worn especially when 
using the carbon arc. 

Selecting a Welding* Outfit. Welding outfits may be of the 
stationary or the portable type. These may also be divided into 
motor-generator sets and the <f transformer" types. Both d.e. 
and a.c. current may be used primarily, depending on the ap- 
paratus employed and the source of current available. 

Regarding the selection of any particular outfit J. M. Ham, 
writing in the General Electric Review for December, 1918, says: 

Few things electrical have in so short a period of time 
created such wide-spread interest as that of arc welding. En- 
gineers having to do with steel products, in whatever form 
produced or in whatever way employed, have investigated its 
uses not only as a building agent when applied to new material 
but as a reclaiming agent for worn or broken parts. In both 
cases its possibilities as a means of greatly increasing output 
and in saving otherwise useless parts at a small fraction of their 
original or replacement value has proved astounding. 

Out of these investigations have grown several systems of 
arc welding. 

To exploit these is the duty of the sales department and the 
measure of its success depends upon the quality of service 
rendered. 

The difficulties of giving service are perhaps not fully ap- 
preciated. Where so many systems have been called for and 



22 ELECTRIC WELDING 

where so many individual ideas have to be met, the problems 
of the manufacturer become multiplied. 

During a period of freight congestion when locomotives were 
in unprecendented demand, an engine was run into the repair 
shop with slid flat spots on each of the eight driving wheels, 
and orders were issued to return it ready for service in record 
time. In three hours repairs had been completed by means of 
the electric arc (to have put on new tires would have required 
three to four days) and the locomotive was out on the road. 
Many other achievements as remarkable as these have been 
obtained. 

It would seem that having demonstrated the success of arc 
welding for a given line of work, others similarly engaged 
would be keen to take advantage of it; but that is true only 
in part, possibly because this is a "show me" age. 

When it becomes apparent to the investigator of arc welding 
possibilities that the process fulfills his reqiiirements, the ques- 
tion of what system to employ confronts him; salesmen are on 
the job to tell him about their particular specialties. He is 
informed that the real secret of welding is having the proper 
electrode (the salesman's special kind) ; it must be covered or 
bare, as the case may be, and contain certain unnamed in- 
gredients. The merits of the direct-current system are extolled. 
Alternating-current outfits are advocated by others, it being 
claimed that they bite deeper and weld if the arc is held. The 
prospective buyer retires with a headache to think it over. 

There is no mystery about arc welding. It is being done 
with all sorts of outfits and many varieties of electrodes. It 
can even be done from power lines with resistance in series with 
the arc. But these systems differ widely in essentials, just as 
in the case of automobiles. "We can buy a cheap car or an 
expensive car, and in either event we get just about what we 
pay for. 

The arc-welding set must pay its way. It must earn dividends 
and conserve materials, and when properly selected and applied 
does both of these things to a degree quite gratifying. To the 
discriminating purchaser it is not sufficient merely to know that 
an outfit will make a weld, he wants to know if it is the best 
weld that can be made, if it can. be made in the shortest possible 
time,- and whether the ratio between cost of the entire system 



ARC WELDING EQUIPMENT 23 

to the savings affected is the lowest obtainable. He doubtless 
will, if the work is of sufficient magnitude to warrant, establish 
a welding department with a trained arc welding man in charge, 
and see that this department stands on its own feet. By so doing 
he places responsibility on a man who knows what to do and 
how to do it a friend rather than a foe of the system. He 
will, other things being anything like equal, respect the opinion 
of the operator in the selection of the system to be employed, 
because it is better to provide a man with tools he is familiar 
with and prefers to use, rather than to force him to use some- 
thing with which he is unfamiliar or which he regards with 
disfavor. 

Obviously, the purchaser wishes to know that the companies 
he is dealing with are reliable and responsible, that the experience 
back of the salesmen is sufficient to warrant faith in his product. 
It is important to know the amount of power required per 
operator and whether drawing the needed amount from his own 
lines or from those of the power company will interfere with 
the system, and if so to what extent, and what, if any, additional 
apparatus will be needed to correct the trouble. Having 
determined these things to his satisfaction, he can install his 
are-welding system with a considerable degree of assurance that 
there will be a decided saving in time, men, and money, and a 
genuine conservation of materials. 

EYE PROTECTION IN IRON WELDING OPERATIONS 

In the General Electric Review for Dec., 1918, "W. 8. Andrews 
says in part: 

Radiation from an intensely heated solid or vapor may be divided tinder 
the three headings: 

(1) Invisible infra-red rays 

(2) Visible light rays 

(3) Invisible ultra-violet rays. 

There is no clear line of demarcation between these divisions, as they 
melt gradually one into the other like the colors of the visible spectrum. 
When the heated matter is solid, such as the filament of an incandescent 
lamp, the visible spectrum is usually continuous, that is, without lines or 
bands; but when it is in the form of a gas or vapor, as in the iron arc 
used for welding operations, the spectrum is divided up into bands or is 
crossed by lines which are characteristic of the element heated. 



24 ELECTRIC WELDING 

The radiations under the foregoing three headings, although of common 
origin, produce very diverse effects upon our senses. Thus, the infra-red 
rays produce the sensation of heat when they fall on our unprotected skin, 
but they are invisible to our eyes. The visible light rays enable us to 
see; but we have no sense that perceives the ultra-violet rays, so that we 
know of them only by their effects. 

The intense glare emitted in the process of arc welding consists of 
a combination of all these rays, and special safety devices are required to 
protect the operator from their harmful effects. 

For welding with acetylene and for light electric welding, it may be 
necessary only to protect the eyes with goggles fitted with suitable colored 
glasses. 

A hand shield made of light wood, and which has a safety colored 
glass window in the center is also sometimes used. This device is used 
for medium weight electric welding done with one hand. The shield serves 
the double purpose of protecting the eyes of the operator and also shielding 
his face from the heat rays and the ultra-violet radiation, which might 
otherwise cause a severe sunburn effect. 

For heavy electric welding, which requires the use of both hands, 
it is common practice for the operator to protect his eyes and neck with 
a helmet fitted with a round or rectangular window of safety glass. These 
helmets are usually made of some strong light material such as vulcanized 
fiber and are designed so that they can be slipped on and off easily, 
the weight resting on the shoulders of the operator. 

There are a great many different kinds of special safety glasses on 
the market, and many combinations of ordinary colored glass are also 
in common use, so a brief discussion of this very important subject is 
in order. 

It is well known that the normal human eye shows considerable chromatic 
aberration towards the red and blue-violet ends of the spectrum and that 
this defect is completely corrected in regard to the middle colors. It, 
therefore, naturally follows that a much clearer definition of an object 
is obtained by combinations of yellow-green light than by red alone, or 
especially by blue or violet light alone. The eye is also more sensitive 
to the yellow and green rays than it is to the red and blue rays; or in 
other words, yellow-green light has the highest luminous efficiency. This 
may easily be verified by looking at a sunlit landscape or fleecy clouds 
in a blue sky through plates of different colored glass. A glass of a light 
amber color or amber slightly tinted with green will clearly bring out 
details that are hardly observable without the glass, and which will be 
obscured entirely by a blue or violet glass. It is therefore obvious that in 
order to obtain the clearest definition or visibility with the least amount 
of glare, the selection of the color tint in safety glasses should properly 
be decided by an expert; but the depth of tint or, in other words, the 
amount of obscuration may be determined best by the operator himself, 
owing to the individual difference in visual acuity which will permit one 
man to see clearly through a glass that would be too dark for another man. 

When the invisible infra-red rays encounter any material which they 



ARC WELDING EQUIPMENT 25 

cannot penetrate, or which is opaque to them, they are absorbed and are 
changed into heat. Hence, *they are frequently termed heat rays. It is, 
therefore, very necessary to guard the eyes from these rays; and although 
they are absorbed to a certain extent by ordinary colored glass, this is 
not sufficient protection against any intense source. There are, however, 
several kinds of glass, which, although fairly transparent to visible light, 
are wonderfully efficient in absorbing heat. The effects of even low-power 
heat rays, when generated in close proximity to the eyes for considerable 
time, are often serious, as is evidenced by the fact that glass blowers, 
who use their unprotected eyes near to hot gas flames of weak luminous 
intensity, are frequently afflicted with cataract which might be positively 
avoided by wearing properly fitted spectacles. 

In selecting colored glasses, great care should be taken to discard all 
samples that show streaks or spots, as these defects are liable to produce 
eye-strain. The glass should be uniform in color and thickness throughout, 
and the colored plate should be protected from outside injury by a thin 
piece of clear glass that can easily be renewed. 

Table II indicates roughly the percentage of heat rays transmitted 
by various colored glasses of given thickness. The source of heat used 
was a 200-watt, gas-filled Mazda lamp operating at a temperature of about 
2400 deg. C. Although the figures are substantially correct for the samples 
tested, they would necessarily vary somewhat for other samples of different 
thickness and degrees of coloration, so that they can be taken only as a 
general guide for comparative purposes. Examination of the table will 
show that the last three, or commercial samples, all show better than 90 
per cent exclusion of the heat rays. 

TABLE II. QUALITIES OF VARIOUS KINDS OF GLASS 

Per Cent 

Thickness Heat Bays 
in Inches Trans- 
Kind of Glass mitted 

Clear white mica 0.004 81 

Clear window glass 0.102 74 

Flashed ruby 0.097 69 

Belgium pot yellow 0.126 50 

Cobalt blue 0.093 43 

Emerald groon 0.100 36 

Dark mica 0.007 15 

Special light green glass 0.095 10 

Special dark glass 0.096 4 

Special gold-plated glass 0.114 0.8 

As to the invisible ultra-violet rays, they are principally to be feared 
not only because they are invisible, but because we have no organ or 
sense for detecting them, and we can only trace their existence by their 
effects. In all cases, however, when we are forewarned of their presence, 
they are very easily shielded, for there are only a few substances which 



26 ELECTRIC WELDING 

are transparent both to visible light and to ultra-violet radiation. Foremost 
among these latter substances, because it is most common, is clear natural 
quartz or rock crystal, from which the so-called "pebble 7 ' spectacle lenses 
are made. Fluorite and selenite are also transparent to ultra-violet rays, 
but these crystalline materials are rare and not in common use. However, 
a moderate thickness of ordinary clear glass, sheets of clear or amber 
mica, and of clear or colored celluloid or gelatine are opaque to these 
dangerous rays. As a ease in point, it is well known that the mercury 
vapor lamp, when made with a quartz tube, is an exceedingly dangerous 
light to the eye, being a prolific source of ultra-violet radiation, so that 
when it is used for illumination, it is always carefully enclosed in an 
outer globe of glass. When the mercury vapor lamp, however, is made 
with a clear glass tube it is a harmless, if not very agreeable, source of 
light, because the outer tube of clear glass is opaque to the ultra-violet 
rays that are generated abundantly within it by the highly luminescent 
mercury vapor. 

When operating with a source of light that is known to be rich in 
ultra-violet rays, such as the iron arc in welding operations, it is not- 
sufficient to guard the eyes with ordinary spectacles because these invisible 
rays are capable of reflection, just the same as visible light, and injury 
may easily ensue from slanting reflections reaching the eye behind the 
spectacle lenses. Goggles that fit closely around the eyes are the only 
sure protection in such cases. Also, when using a hand shield it should 
be held close against the face and not several inches away from it. 

It may here be mentioned that the invisible ultra-violet rays, when they 
are not masked or overpowered by intense visible light, produce the curious 
visible effect termed " fluorescence ' ' in many natural and artificial corn- 
pounds. That is, these rays cause certain compounds to shine with various 
bright characteristic colors, when by visible light alone they may appear 
pure white or of some weak neutral tint. Thus, natural willemite, or zinc 
silicate, from certain localities (which may also le made artificially) 
shows a bright green color under the light from a disruptive spark between 
iron terminals,- whereas this compound is white or nearly so by visible 
light. Also, all compounds of salicylic acid, such as the sodium salieylate 
tablets which may be bought at any drug store, are pure white when seen 
by visible light, but show a beautiful blue fluorescence under ultra-violet 
rays. Many other chemical compounds could be mentioned which possess 
this curious property, but the above substances will suffice to illustrate 
the effect of fluorescence produced by ultra-violet rays, and by which these 
rays may be thereby detected. It must, however, be noted that these 
substances will only show their fluorescent colors very faintly when viewed 
by the light of the low-tension iron are used in welding, because the intense 
visible light of this arc will overpower the weaker effect of the invisible 
ultra-violet rays. The true beauty of fluorescent colors can only be seen 
under a high-tension disruptive discharge between iron terminals, the visible 
light in this case being weak while the ultra-violet rays are comparatively 
intense. 

Summarizing the effective means for eye protection against the various 



ARC WELDING EQUIPMENT 27 

harmful radiations that arc particularly associated with welding operations: 

(1) The intense glare and flickering of the visible rays should be 
softened and toned down by suitably colored glasses, selected by an expert 
and having a depth of coloration which shows the dearest definition com- 
bined with sufficient obscuration of glare, which last feature can be best 
determined by the individual operator. 

(2) When infra-red rays are present to a dangerous degree, a tested 
heat-absorbing or heat-reflecting glass should be employed, either in com- 
bination with a suitable dark colored glass, wRen glaring visible light is 
present, or by itself in cases where the visible rays are not injuriously 
intense. 

(3) In guarding the eye from the dangerous ultra-violet rays, it must 
be carefully noted that lt pebble" lenses are made from clear quartz 
or natural rock crystal, and this material being transparent to these rays 
offers no protection against their harmful features. On the other hand, 
ordinary clear glass is a protection against these rays when they are not 
very intense, but dark-amber or dark-ambcr-green glasses are absolutely 
protective. Glasses showing blue or violet tints should be avoided, excepting 
in certain combinations wherein they may be used to obscure othor colors. 



CHAPTER III 
DIFFERENT MAKES OF ARC WELDING SETS 

In showing examples of different makes and types of arc 
welding sets, only enough will be selected to cover the field in 
a general way, and no attempt whatever will be made to make 
the list complete. 

The General Electric Co., Schenectady, N. Y., puts out the 




FIG. 22. General Electric 3-KW., 1700-K.P.M., 125-60-20-V. Compound- 
wound Balancer-Type Arc Welding Set. 

constant energy metallic electrode set shown in Pig. 22. This, 
however, is but one type of its machines as this company makes 
a varied line covering all needs for welding work. Two of their 
commonly used, up-to-date sets are illustrated in Figs. 131 and 
132, Chapter VIII. 

This particular machine combines high arc efficiency and 
light weight. The balancer set is of the well-known G-E standard 
"MCC" construction. It is built for operation on 125-v., d.c. 
supply circuits, which may be grounded on the positive side only, 
and is rated "MCC" 3 kw., 1,700 revolution, 125/60/20 v., com- 

28 



DIFFERENT MAKES OF ARC WELDING SETS 29 

pound-wound, 150 amperes, RC-27-A frames, the two armatures 
being mounted on one shaft and connected in series across the 
125-v. supply circuit, one welding circuit terminal being taken 
from the connection between the two armatures and the other 
from the positive line. By this means each machine supplies 
part of the welding current and, consequently, its size and weight 
is minimized. The design of the fields and their connections 
is such that the set delivers the voltage required directly to the 
arc without the iise of resistors or other energy-consuming 
devices. The bearings are waste packed: this type of bearing 




FIG. 23. Welding Control Panel for Balancer Set. 

being desirable in a set which is to be made portable either for 
handling by a crane or for mounting on a truck. 

The welding control panel for the balancer set is shown in 
Fig. 23. This panel consists of a slate base, 24r-in. square, which 
is mounted on 24-in. pipe supports for portable work and on 
64-in. pipe supports for stationary work. 

The entire set consists of one ammeter, one voltmeter, one 
dial switch, two field rheostats (motor and generator) one start- 
ing equipment with" fuse, one reactor mounted on the pipe frame 
work of panel. The ammeter and voltmeter are enclosed in a 
common case. The ammeter indicates current in the welding 



30 



ELECTRIC WELDING 



circuit and the voltmeter is so connected that by means of a 
double-throw switch, either the supply line voltage or the welding 
line voltage can be read. 

The dial switch is connected to taps in the series field of 





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FIG. 24. Balancer and Control Panel Connections for General Electric 
Constant-Energy Constant-Arc Set. 

the generator, the field being connected to oppose the main field. 
This feature provides the current control by which six steps 
are obtained of the approximate values of 50, 70, 90, 110, 130 and 
150 amp., which enables the operator to cover a very wide range. 



DIFFERENT MAKES OF ARC WELDING SETS 



31 



In addition, if intermediate current values are required, they can 
be obtained by means of the generator field rheostat. 

A small reactor is used to steady the arc and current both 
on starting and during the period of welding. 

Arc welding is usually done on metal which is grounded and 
this is especially unavoidable in ship work, where the ship struc- 
ture is always well grounded. Since successful operation requires 
that the positive terminal be connected to the work the supply 
circuit should be safely grounded on the positive side. 

Where a 125-v., d.e. supply system is not available, standard 




Thickness 

FTG. 25. Carbon Electrode Cutting Speeds for Different Thicknesses 

of Plate. 

"MIC" or "MCC" sets arc furnished to supply power at 125 v., 
the motor being either 3-phase, 60-cycle, 220, 440 or 550 v., or 
cl.c., 230 or 550 v., and in three capacities, 5-J kw., 7 kw., and 
15 kw. "With each motor generator set there is supplied a panel 
containing 1 generator field rheostat and motor starter, which may 
be mounted beside the balancer panel. A diagram showing the 
balancer and control panel is shown in Pig. 24. 

The constant energy are-welding equipment supplies, to the 
arc, practically constant energy throughout the welding range 
for metallic electrode welding only. If the arc is lengthened 
slightly the voltage increases and the current decreases, the total 



32 



ELECTRIC WELDING 





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DIFFERENT MAKES OF ARC WELDING SETS 



33 



energy being practically constant. As the voltage required by 
the arc varies, the generator readjusts itself to this condition 
and automatically supplies the required voltage; the remainder 
being utilized by the motor end of the set. The interchange 
of voltage between the motor and generator is practically in- 
stantaneous, no perceptible lag occurs. This feature is valuable 
when metal drops from the electrode and causes an instantaneous 
increase in current. The commutation is sparkless and the weld- 




Fl. 26. Wilson Two- Are, 300 Amp., "Plastic Arc" Welding Set. 

ing circuit may be short-circuited without injury to the machine, 
In connection with welding with an outfit of this kind, the 
practical man and student will find Table III of considerable 
interest. For sheet steel cutting using the carbon arc, the 
chart Fig. 25 is given. 

The Wilson Outfit. The Wilson "plastic are" process and 
apparatus was first developed in railroad work by the Wilson 
Welder and Metals Co., New York, in order to enable the 
welder to control the heat used. By this system it is claimed 



34 ELECTRIC WELDING 

that any number of operators can work from one large machine 
without one welder interfering in any way with the work of 
another. Each operator can have properly controlled heat and 
a steady arc at the point of application. This system was 




FIG. 27. Welding and Cutting Panel for Wilson Set. 

largely used in the repair of the damaged engines on the Ger- 
man ships which were seized by us. By regulating the heat 
it is claimed that any metal can be welded without preheating. 
A two-arc set is shown in Fig. 26 and a close-up of a control 
panel in Fig. 27. 



DIFFERENT MAKES OF ARC WELDING SETS 35 

This outfit consists essentially of a constant voltage 
generator driven by any constant-speed motor, all mounted 
on a common bedplate. The regulation of the welding current 
is maintained by means of a series carbon pile acting as a 
series resistance of varying quantity under the action of increas- 
ing or decreasing mechanical pressure. This pressure is 
produced by means of a series solenoid operating mechanically 
on a lever and spring system which varies the pressure on 
the carbon pile inversely as the current in the main circuit. 
This establishes a constant current balance at any predeter- 
mined adjustment between a maximum and minimum range 
designed for. The change in adjustment is controlled by the 
operator at the point of work by means of a small pilot motor 
which shifts the lever center of the pressure mechanism, 
thereby raising or lowering the operating current. This system 
maintains a constant predetermined current at the arc regard- 
less of the arc length. The operation of the mechanism is 
positive and quick acting. A special series choke-coil is 
mounted on the control panel for use as a cutting resistance. 

"Plastic Arc" Dynamotor Unit. The " plastic arc" weld- 
ing unit illustrated in Pig. 28, while embodying the same 
fundamental principles as the foregoing, is a later model. This 
set is composed of a dynamotor and current control panel. 
The generator is flat-compound wound, and maintains the 
normal voltage of 35 on either no load or full load. 

The control panel has been designed to provide a constant- 
current controlling panel, small in size, of light weight, simple 
in operation and high in efficiency. The panel is of slate, 
20 in.X27 in., and on it are mounted a small carbon pile, a 
compression spring, and a solenoid working in opposition to 
the spring. The solenoid is in series with the arc so that any 
variation in current will cause the solenoid to vary the pressure 
on the carbon pile, thereby keeping the current constant at the 
value it is adjusted for. 

Three switches on the panel provide an easy means of cur- 
rent adjustment between 25 and 175 amperes. The arrange- 
ment of the welding circuit is such that 25 amperes always 
flow through the solenoid when the main switch is closed, 
whether the welding current is at the minimum of 25 amperes 
or the maximum of 175 amperes. The balance of the welding 



36 



eurre nt is taken care 
the solenoid. 



ELECTRIC WELDING 
of in by-pass resistances shunted around 
as a dynamotor unit, with 




28.- "PtartlA" Dynamotov WCMms Unit. 



be temsW without a motor, to bo bdt driwn The nor 

b 



.. 

motor The acts can be mounted on a truck tor < 
-Th. porUUc a,,,,,.,.!!,, outfit ! 



DIFFERENT MAKES OF ARC WELDING SETS 



37 



trated in Fig. 29 is the product of the Lincoln Electric Co., 
Cleveland, Ohio. The outfit is intended for operation where 
electric current is not available and consists of a 150-amp. 
arc-welding generator direct connected to a Winton gasoline 
engine. An interesting feature of the machine is the method 
used to insure a steady arc and a constant and controllable 
heat. A compound-wound generator is used, the series wind- 




FIG. 29. Lincoln Self-Contained Portable Set. 

ings of which are connected to oppose the shunt field, the two 
windings being so proportioned that the voltage increases in 
the same ratio that the current increases, thus limiting the 
short-circuit current. Another important effect of this is that 
the horsepower, and therefore the heat developed for a given 
setting of the regulator switch shown on the control board 
above the generator remains practically constant. It is claimed 
that this method of control gives considerably more work 



38 



ELECTRIC WELDING 



on a given amount of electricity than where the machines use 
the ballast resistance. Additional arc stability is insured by 
the stabilizer at the right of the illustration, this being a highly 
inductive low-resistance coil connected in the welding circuit 
and serving to correct momentary fluctuations of current. 

Westinghouse Single-Operator Electric Welding Outfit. 
The single-operator electric arc-welding equipment shown in 
Fig. 30 is manufactured by the "Westinghouse Electric and 
Manufacturing Co., East Pittsburgh, Pa. The generator 




FIG. 30. Westinghouse Single-Operator Portable Outfit. 

operates at arc voltage and no resistance is used in circuit 
with the arc. The generator is designed to inherently stabilize 
the arc, thereby avoiding the use of relays, solenoid control- 
resistors, etc." 

The generator has a rated capacity of 175 amp. and is 
provided with commutating poles and a long commutator, 
which enable it to carry the momentary overload at the instant 
of striking an arc without special overload device. Close adjust- 
ment of current may be easily and quickly made, and, once 



DIFFERENT MAKES OF ARC WELDING SETS 



39 



made, the amount of current at the weld will remain fixed 
within close limits until changed by. the operator. There arc 
twenty-one steps provided which give a current regulation of 
less than 9 amp. per step and make it much easier for a welder 
to do vertical or overhead work. 

The generator is mounted on a common shaft and bedplate 
with the motor. A pedestal bearing is supplied on the com- 
mutator end and carries a bracket for supporting the exciter 
which is coupled to the common shaft. Either d.c. or a.c. 
motors can be supplied. Where an a.c. motor is used leads 




FlG. 31. U. S. L. Portable, A-C. Motor-Generator Set. 

are brought outside the motor frame for connecting either 
220- or 440-v. circuits. An electrician can change these con- 
nections in a few minutes' time. This feature is desirable on 
portable outfits which may be moved from one shop to another 
having a supply circuit of different voltages. For portable 
service, the motor-generator set with the control panel is 
mounted on a fabricated steel truck, equipped with roller- 
bearing wheels. The generator is compound-wound, flat com- 
pounded, that is, it delivers 60 v. at no-load and also at full- 
load. 



40 ELECTRIC WELDING 

The U. S. Light and Heat Co.'s Outfit. The portable outfit, 
Fig. 31, is made by the U. S. Light and Heat Corp., Niagara 
Falls, N. Y. It is 28 in. wide, 55 in. high, 54 in. long, and 
will pass through the narrow aisle of a crowded machine shop. 
It weighs 1,530 Ib. complete. In case a d.c. converter is used, 
the weight is about 125 Ib. less. Curtains are provided to keep 
out dirt. A substantial cable feel is provided carrying two 
50-ft. lengths of flexible cable for carrying the current to the 
arc. The reel is controlled by a spring which prevents the 
paying out of more cable than the welder needs. The outfit 
is made in several models to use 4 kw., 110-220-440-550 v., 
2 and 3 phase, 25 and 60 cycle. 

The Arc Welding Machine Co.'s Constant-Current Closed- 
Circuit System. The constant-current closed-circuit arc welding 




FIG. 31A. -The Arc Welding Machine Co.'s Outfit. 

developed by the Arc "Welding Machine Co., New York, 
permits the use of an inherently regulating generator with more 
than one arc on a single circuit. This system is claimed to be 
especially adapted to production welding applications. 

The method has all the advantages of series distribution, 
namely, the size of wire is uniform throughout the system and 
carries a uniform current, independent of the length of the 
circuit as well as of the number of operators. The circuit is 
simply a single wire of sufficient cross-section to carry the 
current for one arc, run from the generator to the nearest arc, 
from there to the next, and so on back to the generator. 
Wherever it is desired to do welding, a switch is inserted in 
the line, and a special arc controller provided with suitable 
connections is plugged in across the switch whenever work 



DIFFERENT MAKES OF ARC WELDING SETS 41 

is to be done. These controllers may be made portable or 
permanently mounted at the welding station. 

The set shown in Fig. 31A consists of two units: The 
generator proper which furnishes the energy for welding, and 
the regulator which automatically maintains the current at a 
constant value. The regulator is excited from a separate 
source, and, by varying its excitation with an ordinary field 
rheostat, the main welding current may be set at any value 
within the range of the machine that is desired, and once set 
it will automatically maintain that value. 

Each arc that is operated on the system is equipped with 
an automatic controller which serves two essential purposes : 

1 It maintains at all times the continuity of the circuit, 
so that one arc cannot interfere with any of the 
others when it comes on, or goes out of, the circuit. 

2 It controls automatically the heat which can be put 
into the metal of the weld. 

The current through the arc, together with the size of the 
electrode, determines the flow of metal from the electrode, and 
this current is adjusted by shunting .a portion of the main 
current around the arc. The regulation characteristic of the 
arc may be adjusted by a series parallel resistance, which is 
one of the special features. "When doing work on very thin, 
light metals, especially where the weld must be tight, it is 
necessary that fusion take place from the first instant the 
arc is struck. If the heat of the arc is exactly right for 
continuous operation, it will, not be enough at the first instant, 
and if it is sufficient to produce fusion at once, then it will 
be too much a few seconds later. On this account a special 
type of controller is used for such work which provides for 
automatic reduction at a definite time after the are is actually 
started, and continuing for a definite time and at a definite 
rate. Both periods of time and the rate and magnitude of 
the current change arc adjustable. 

For a given flow of metal through the are the temperature 
of the metal is determined by the length of the arc, that is, 
by the voltage. With this controller, the length of the arc 
limited by the voltage is adjusted to suit the work and the 
operator, and if exceeded, the arc is short-circuited automat- 



42 ELECTRIC WELDING 

ically and remains short-circuited until the welder is ready 
to begin again. 

Provision is also made for stopping the arc at will without 
lengthening it. Therefore it is claimed that with this system 
it is impossible to draw a long arc and burn the metal. The 
arc is not broken when the welding operation is stopped, but 
is killed by a short-circuit which is placed across it. 




FIG. 32. Zeus Arc-Welding Outfit. 

Stopping an are by short-circuiting and limiting the heat 
production in the same way is a patented feature. 

"Zens" Arc-Welding Outfit. The "Zeus" arc-welding out- 
fit shown in Pig. 32 is a product of the Gibb Instrument Co., 
1644 Woodward Ave., Detroit, Mich. In this device the motor- 
generator customarily used has been supplanted by a trans- 



DIFFERENT MAKES OF ARC WELDING SETS 43 

former with no moving parts. The outfit is built on a unit 
system, which allows the installation of a small outfit, and 
if the work becomes heavier a duplicate set may be connected 
in parallel. One of the features of the machine is the arrange- 
ment for regulation. It is not necessary to change any con- 
nection for this purpose, as a wheel connected with a secondary 
and placed on the top of the case raises and lowers this 
secondary, and provides the regulation of current necessary for 




FIG. 33. Arcwcll Outfit for Alternating Current. 

different sizes of electrodes. The inherent reactance of the 
outfit automatically stabilizes the arc for different arc lengths. 
The Arcwell Outfit. The Arcwell Corporation, New York, 
has on the market an electric welding apparatus built for 
operation on alternating current of any specified voltage or 
frequency. It is shown in Fig. 33. It differs from the com- 
pany's standard outfit in that it is being put out expressly 
for the use of smaller machine shops and garages, its capacity 
not being sufficient to take care of heavy work on a basis of 



44 ELECTRIC WELDING 

speed. It will do any work that can be done by the large 
machines, but the work cannot be performed as rapidly, th 
machine being intended especially for use by concerns wh 
have only occasional welding jobs to perform. The machir 
weighs approximately 200 Ib. and, being mounted on caster 
it can be moved from one job to another. 

Alternating-Current Arc-Welding Apparatus. The Elects- 
Arc Cutting and Welding Co., Newark, N. J., is now marketir 
the alternating-current are-welding outfit shown in Fig. 34. 

This illustration shows the entire apparatus for use on 




34. Apparatus Made by the Electric Are Cutting and "Welding < 



single-phase circuit, the current being brought in through t 
wires seen protruding at the lower left corner. 

The device consists principally of a transformer with 
moving parts and is claimed to last indefinitely. In this a 
paratus, instead of holding either current or voltage const a 
as with direct-current sets, the wattage, or the product 
voltage and current, is held constant. The alternating-currc 
set holds the arc wattage without moving parts ; hence the he 
is substantially constant for any given setting, and it is claim 
that as soon as any person becomes accustomed to the sou 
and sight of the arc and can deposit the molten metal whc 
he desires it is impossible to burn the metal from too mn 
heat or make cold-shut welds from too little heat. The amoi 



DIFFERENT MAKES OF ARC WELDING SETS 45 

Qf heat generated is controlled by means of an adjusting handle 
on the transformer together with taps arranged on a plugging 
board. It is stated that the kilowatt-hours required to deposit 
a pound of mild steel with this machine varies from 1| to 2|-. 
Their largest set is a 60-cycle type weighing about 200 lb., 
which places it in the portable class. The set can be furnished 
for any a.c. power supply, but it is not advisable to use a 
greater voltage than 650 on the primary. The set can also be 
made single phase, two phase three wire, two phase four wire, 








FIG. 35. General Electric Lead-Burning Outfit. 

to operate across the outside wires of the two-phase system 
or from a three-phase power supply. Polyphase sets are about 
30 per cent heavier than the single-phase sets. In the two- 
phase machine balanced current can be drawn from each of 
the two phases by placing the sets across the oxitside wires. 
This is advocated, as it provides for leading current on one 
phase which brings up the total power factor of the system and a 
better power rate can be obtained. In polyphase circuits where 
more than one set is used single-phase sets can be distributed 
among the several phases. 

The outfit can be made especially for welding and for cut- 



46 ELECTRIC WELDING 

ting or for combination welding and cutting and can make 
use of bare wire, slag-covered, gaseous fluxed or carbon elec- 
trodes. An operator's mask and the electrode holder used 
may be seen on top of the apparatus. 

General Electric Lead-Burning Transformer. This lead- 
burning transformer, Fig. 35, a product of the General Electric 
Co., Schenectady, N. Y., can be used for lead burning, soldering 
electric terminals, splicing wires and tinsmith jobs, and even 
brazing can be done by placing the work between a blunt 
carbon point and a piece of cast iron. The transformer is 
designed to be connected to the ordinary 110-v., a.c. lighting 
circuit. Heavy rubber-covered terminal leads are used to 
convey the low-voltage, heat-producing current to the work, 
one terminal ending in a clip for fastening to some convenient 
portion of the work while the other terminal has a carbon 
holder arranged with an insulated handle. When the welding 
carbon is brought into contact with the work the pointed end 
becomes intensely hot and melts the metal over a restricted 
area. It should be noted that no arc is drawn, the end of 
the carbon point being heated to such a temperature that the 
metal in the vicinity is melted. The device uses about 800 
watts while in actual use, the consumption dropping to 4| 
watts when the point is removed from, the work. It is stated 
that the device is very convenient in plumbing, roofing and 
tank-building jobs, as well as other such work. 



CHAPTER IV 
TRAINING ARC WELDERS 

Writing on the training of arc welders, in the American 
Machinist, April 15, 1920, 0. H. Eschholz, research engineer 
of the Westinghouse Electric and Mfg. Co., Pittsburgh, says: 

Many industrial engineers are now facing the problem of 
developing competent welders. This situation is attributed to 
the rapid growth of the metallic electrode arc-welding field 
as the result of the successful application of the process to 
war emergencies. The operator's ability, it is now generally 
conceded, is the most important factor in the production of 
satisfactory welds. To facilitate the acquirement of the neces- 
sary skill and knowledge, the following training course con- 
siders in their proper sequence the fundamental characteristics 
and operations of the bare metallic electrode arc-welding 
process. 

It is well known that the iron arc emits a large quantity 
of ultra-violet radiation. Protection from the direct rays is 
usually afforded by the use of hand shields. Many uncom- 
fortable burns, however, have been traced to reflected radiation. 
To secure adequate protection from both direct and reflected 
light it is necessary for the welder to use a fiber hood equipped 
with suitable glasses. Paper No. 325 of the Bureau of 
Standards on " Spectroradiometric Investigation of the Trans- 
mission of Various Substances" concludes that the use of amber 
and blue glasses will absorb most of the ultra-violet as well 
as infra-red radiation. To protect the operator from incan- 
descent particles expelled by the arc, closely woven clothing, 
a leather apron, gauntlets and bellows-tongued shoes should 
be worn. 

If the welding booth is occupied by more than one welder, 
it will he found desirable to equip each operator with amber 
or green-colored goggles to reduce the intensity of accidental 

47 



48 



ELECTRIC WELDING 



"flashes" from adjacent arcs after the welder has removed 

his hood. 

The Welding 1 Booth. The difficulty of maintaining an arc 
is greatly increased by the presence of strong air currents. To 
avoid the resulting arc instability, it is desirable to inclose 
the welder on at least three sides, with, however, sufficient 
ventilation provided so that the booth will remain clear from 
fumes. By painting the walls a dull or matte black the amount 
of arc radiant energy reflected is reduced. 

The electrode supply and means of current control should 
be accessible to the operator. When using bare electrodes the 
positive lead should be firmly connected to a heavy steel or 
cast-iron plate, mounted about 20 in. above the floor. This 
plate serves as the welding table. 

Welding" Systems. Many commercial sets compel the 
operator to hold a short arc. This characteristic favors the 
production of good welds but increases the difficulty of main- 
taining the arc. By increasing the stability of the arc through 
the use either of covered electrodes, series inductances or in- 
creased circuit voltage and series resistance, the acquisition of 
the purely manipulative skill may be accelerated. 

The Electrode Holder. The electrode holder should remain 
cool in service, shield the welding hand from the arc, facilitate 
the attachment and release of electrodes, while its weight, 
balance and the drag of the attached cable should not produce 
undue fatigue. A supply of different types of covered and 
bare electrodes should be carried by the welding school so 
that the operator may become familiar with their operating 
and fusing characteristics. 

The degree of supervision the welder is to receive de- 
termines the source of operator material. If the welding opera- 
tions are to be supervised thoroughly and the function of the 
welder is simply that of uniting suitably prepared surfaces, 
the candidate may be selected from the type of men who usually 
become proficient in skilled occupations. If, however, the 
responsibility of the entire welding procedure rests upon the 
operator, he should be drawn from members of such metal 
trades as machinist, boilermaker, blacksmith, oxy-acetylene 
welder, etc. Some employers find it expedient to use simple 
eye and muscular co-ordination tests to determine the candi- 



TRAINING ARC WELDERS 49 

date's ability to detect the colors encountered in welding and 
to develop an automatic control of the arc. 

With adequate equipment provided, the operator may be 
instructed in the following subjects: 

1. Manipulation of the arc. 

2. Characteristics of the arc. 

3. Characteristics of fusion. 

4. Thermal characteristics. 

5. Welding procedure. 

6. Inspection. 

Arc Manipulation. A sitting posture which aids in the 
control of the arc is shown in Pig. 36. It should be noted that 




FIG. 36. Correct Welding Posture and Equipment. 

by resting the left elbow on the left knee the communication 
of body movements to the welding hand is minimized, while by 
supporting the electrode holder with both hands the arc may 
be readily directed. During the first attempts to secure arc 
control covered electrodes may be used, as these greatly increase 
arc stability, permitting the welder to observe arc characteris- 



50 ELECTRIC WELDING 

tics readily. It is suggested that throughout the training period 
the instructor give frequent demonstrations of the welding 
operations as well as occasionally guide the apprentice's weld- 
ing arm. 

Arc Formation. With the welding current adjusted to 100 
amp. and a V 33 -in. covered electrode in the holder, the operator 
assumes the posture shown and lowers the electrode until con- 
tact is made with a mild-steel plate on the welding table, 
whereupon the electrode is withdrawn, forming an arc. If an 
insulating film covers either electrode surface or the current 
adjustment is too low, no arc will be drawn. "With the arc 
obtained the operator should note the following characteristics 
of arc manipulation. 

Fusion of Electrodes. The fusion of electrodes is frequently 
called "sticking" or "freezing." It is the first difficulty 
encountered and is caused either by the use of an excessive 
welding current or by holding the electrodes in contact too 
long before drawing the arc. This fusing tendency is always 
present because the welding operation requires a current den- 
sity high enough to melt the wire electrode at the arc terminal. 
When such fusion occurs the operator commits the natural 
error of attempting to pull the movable electrode from the 
plate. If he succeeds in separating the electrodes, the momen- 
tum acquired, unless he is very skillful, is sufficient to carry 
the electrode beyond a stable arc length. If, however, the wrist 
of the welding hand is turned sharply to the right or left, 
describing the arc of a circle having its center at the electrode 
end, the fused section is sheared and a large movement of the 
electrode holder produces an easily controllable separation of 
the arc terminals. 

Maintenance of Arc. After forming the arc the chief con- 
cern of the welder should be to maintain it until most of the 
electrode metal has been deposited. If the movable electrode 
were held rigidly, the arc would gradually lengthen as the 
electrode end melted off until the arc length had increased 
sufficiently to become unstable and interrupt the flow of cur- 
rent. To maintain a constant stable arc length it is necessary 
for the operator to advance the wire electrode toward the plate 
at a rate equal to that at which the metal is being deposited. 
For the novice this will prove quite difficult. However, if the 



TRAINING ARC WELDERS 51 

initial attempts are made with covered electrodes, which per- 
mit greater arc-length variations than bare electrodes, the 
proper degree of skill is soon acquired. 

When the operator succeeds in maintaining a short arc 
length for some time, the covered electrode should be replaced 
by a Yso-in. diameter bare electrode, the welding current in- 
creased to 150 amp. or 175 amp. and either reactance included 
in the circuit or the voltage of the welding set increased. "With 
increase in manipulative skill the reactance coil may be short- 
circuited or the supply voltage reduced to normal, and practice 
continued under commercial circuit and electrode conditions. 

Further instruction should not be given until the candidate 
is able to maintain a short arc during the entire period required 
to deposit the metal from a bare electrode 14 in. long, r) / 32 i n - 
in diameter, on a clean plate ^ in. in thickness when using 
a welding current of 150 amp. The arc voltage may be used 
as a measure of the arc length. The average arc voltage 
during the test should be less than twenty-five, as this 
corresponds to a length of approximately -J in. Some operators 
meet this test in the first hour of their training, others require 
two or three days' practice. If arc-length control is not 
obtained within the latter period, the instructor may safely 
conclude that the apprentice is physically unfitted for the occu- 
pation of arc welding. If the test is satisfactory, training 
should be continued, using bare electrodes but with such 
stabilizing means as inductance or resistance again inserted in 
the circuit. 

Control of Arc Travel; Direction and Speed. The plate arc 
terminal and the deposited metal follow the direction taken 
by the pencil electrode. The difficulty of forming deposits 
varies with the direction. The first exercise should consist in 
forming a series of deposits in different directions, as shown 
in A, Pig. 37, until the operator develops the ability to form 
a series of straight, smooth-surfaced layers. Additional skill 
may be acquired by the practice of forming squares, circles 
and initials. 

The speed of arc travel determines the height of the deposit 
above the parent metal. A second exercise should require the 
formation of deposit strips having heights of Y 1C , Vs all( i 
Vie in. The normal height of a deposit when using a welding 



52 



ELECTRIC WELDING 



current of 150 amp. and a bare electrode of 5 / S2 in. diameter 
is approximately in. 

Weaving. If the electrode end is made to describe the arc 
of a circle across the direction of deposit formation, the width 
of the deposit, may be increased without changing the height 
of the deposit. This weaving movement also facilitates slag 
flotation and insures a more complete fusion of the deposited 
metal to the parent metal. B and C, Fig. 37, illustrate the 
appearance of deposits formed with and without weaving of 
the electrode. 

A third exercise should consist in forming layers of equal 





A B C 

FIG. 37. Control of Are Direction Exercise. 

(A) Exercise to develop control of arc direction. (B) Effect of weaving elec- 
trode across direction of deposit. ((7) Effect of not weaving. These deposits wore 
formed with the operator and plate in the same relative position, necessitating a 
change in the direction of arc travel for the deposition of each layer. Note that 
this direction is indicated by the position of the crater terminating each strip as 
well as by the inclination of the scalloped surface. 

heights, but having widths of , f , | and f in. when using an 
arc current of 150 amp. and a 5 /3 2 -i n - diameter bare electrode. 

As the welder should now be able to control direction, 
height and width of deposits while maintaining a short arc, 
he should be given the fourth exercise of forming tiers of 
parallel, overlapping layers until inspection of the surface and 
cross-sections of the built-up material indicates good fusion 
of the metal as well as absence of slag and blowholes. 

Arc and Fusion Characteristics. The arc is the welder's 
tool. Its function is to transform electrical energy into highly 



TRAINING ARC WELDERS 53 

concentrated thermal energy. This concentrated energy serves 
to melt both the parent and the deposited metals at the elec- 
trode terminals, the arc conveying the liquefied pencil into the 
crater formed on the material to be welded. 

The plate arc terminal will always appear as a crater if 
a welding current is used. This crater is formed partly by the 
rapid volatilization of the liquefied material and partly by the 
expulsion of fluid metal due to the explosive expansion of 
occluded gases suddenly released or of gases formed by 
chemical reaction between electrode materials and atmospheric 
gases. To secure good fusion the deposited metal should be 
dropped into the crater. This is facilitated by the use of a 
short arc. On welding, the operator should frequently note, 
the depth of arc crater- and manipulate the arc so that the 
advancing edge of the crater is formed on the parent metal 
and not on the hot deposited metal. 

Polarity. When using bare electrodes the concentration of 
thermal energy is greater at the positive than at the negative 
terminal. Since in most welding applications the joint has a 
greater thermal capacity than the pencil electrode, more com- 
plete fusion is assured by making the former the positive elec- 
trode. The difference in concentration of thermal energy may 
be readily illustrated to the welder by having him draw an 
arc from a V ic -in- thick plate with the plate first connected 
to a negative and then to the positive terminal. If a current 
of approximately 60 amp. is used with a Y 10 -in. diameter elec- 
trode, he will be able to form a deposit on the plate, if the 
plate is the negative terminal. On reversing the polarity, how- 
ever, the energy concentration will be sufficient to melt through 
the plate, thus producing a "cutting arc." 

An arc stream consists of a central core of electrically 
charged particles and an envelope of hot gases. The electrode 
material is conveyed in both liquid and vapor form across the 
arc, a spray of small globules being discernible with some types 
of electrodes. Since atmospheric gases tend to diffuse through 
this incandescent metal stream, it is obvious that some of the 
conveyed material becomes oxidized. 

Through the maintenance of a short arc, not exceeding -J 
in., the resulting oxidation is a minimum because enveloping 
oxide of manganese vapor and carbon dioxide gas, formed by 



54 



ELECTRIC WELDING 



the combination of atmospheric oxygen with the manganese 
and carbon liberated from the electrodes, serves as a barrier 
to restrict the further diffusion of atmospheric gases into the 
arc stream. Fig. 38 illustrates the degree of protection afforded 
the conveyed metal when using short and long arcs. With the 
latter convection currents deflect the protecting envelope from 
the arc stream. The effect of arc length on rate of oxidation 
may be clearly indicated to the welder by forming deposits with 
a -J-in. arc and a f -in. arc on a clean plate. 

The surface of the first deposit will be clean and smooth, 
as shown at a, Fig. 39. The surface of the second deposit will 
be irregular and covered with a heavy coating of iron oxide, 
as shown at 6. All oxide formed during welding should be 




FIG. 38. Long and Short Welding Are. 
Large arc stream causes excessive oxidation. 

floated to the surface, since its presence in the weld will reduce 
the strength, ductility and resistance to fatigue of the joint. 
Stability. The ease of maintaining an arc is determined by 
the stabilizing characteristics of the electrical circuit and the 
arc gases. As noted above, increased stability may be obtained 
by the use of series inductance or higher circuit voltage with 
increased series resistance, higher arc currents and covered 
electrodes. A high-carbon-content electrode, such as a drill 
rod, gives a less stable arc than low-carbon content rods, owing 
apparently to the irregular formation of large volumes of arc- 
disturbing carbon-dioxide gas. Bare electrodes after long ex- 
posure to the atmosphere or immersion in weak acids will be 
found to "splutter" violently, increasing thereby the difficulty 
of arc manipulation. This "spluttering" is apparently caused 



TRAINING ARC WELDERS 



55 



by irregular evolution of hydrogen. If the electrode is coated 
with lime, its stability improves. 

The evident purpose of a welding process is to secure fusion 
between the members welded. The factors that determine 
fusion in are welding are are current, electrode current density, 
thermal capacity of joint sections and melting temperatures 
of electrode and plate materials. By observing the contour 
of the surface of the deposited metal as well as the depth of 
the arc crater the welder may determine at once whether such 
conditions under his control as arc current, electrode current 




FIG. 39. Deposit Obtained with Short Are and Long Are. 

Note that surfaces of deposit and plate in (a) are comparatively clean, while 
those in (&) are heavily coated with iron oxide. 

density and electrode material are properly adjusted to produce 
fusion. 

The fifth exercise should consist of forming a series of 
deposHs with arc currents of 100, 150 and 200 amp., using 
electrodes with and without coatings having different carbon 
and manganese content. Cross-sections of the deposits should 
then be polished and etched with a 10 per cent nitric-acid 
solution and the surface critically examined for such evident 
fusion characteristics as penetration and overlap, comparing 
these with the surface characteristics. 



66 



ELECTRIC WELDING 



' /f > 








FIG. 40. Overlap ami Penetration Studies. 

(A) Typical section through a normal layer formed by depositing metal from 
a mild-steel electrode on a mild-steel plate. Note the contour of the deposit a.s well 
as that of the fused zone and the slight overlap and correct depth of deposit pene- 
tration. Parent-metal crystal structure is altered by thermal changes. 

(B) Typical section through a deposit formed when holding a long arc. Ex- 
cessive overlap and no penetration exist. Most weld' failures may be attributed to 
the operator maintaining occasionally or continuously too long an arc. 

(C) Section through crater formed on. completing deposit strip. The depth of the 
crater is a measure of the depth of penetration. 

(D) Excessive overlap secured with a pencil electrode (drill rod) having a 
lower melting temperature than the parent metal (mild steel). 

(E) Elimination of overlap obtained by using a pencil electrode (mild steel) 
having a higher melting temperature titan the parent metal (cast iron). 

(F) Incomplete fusion obtained with a low arc current. 
(<?) "Cutting" secured through use of high arc current. 

(JET) Section indicates proper selection of welding current and electrode diameter 
to secure fusion. 

(I) Poor fusion caused by too rapid flow thermal energy from deposit through 
plates. 

(7) Adequate fusion obtained by increasing arc terminal energy to compensate for 
increased rate of heat flow. 



TRAINING ARC WELDERS 57 

Overlap and Penetration. Examination of the boundary 
line between the deposited and plate metals in A and B, Fig. 
40, reveals that the penetration decreases in both directions 
from the center of the layer, no fusion being evident at the 
edges of the deposit, the contour betraying the extent of this 
overlap. As shown in the penetration may be estimated from 
the crater depression. 

An exaggerated overlap obtained in welding a mild-steel 
plate with a high-carbon-content steel rod, having a lower melt- 
ing point than the plate, is shown in D. The re-entrant angle 
of the deposit edge is plainly evident. E illustrates a condi- 
tion of no overlap in depositing metal from a mild-steel elec- 
trode upon a cast-iron, plate having a lower melting point. 
F and G show respectively the effect of using too-low and too- 
high arc currents. 

The effect of heat conductivity, heat-storage capacity, ex- 
pansion and contraction of the parent metal and contraction 
of the hot-deposit metal must be studied. 

Heat Conductivity and Capacity. The effect of any of 
these factors is to increase the flow of thermal energy from the 
plate arc terminal and therefore to reduce the amount of metal 
liquefied. To maintain a given rate of welding speed it there- 
for becomes necessary to increase the arc current with increase 
in thickness or area of joint. 

A welding current of 150 amp. will produce satisfactory 
penetration on welding the apex of scarfed plates -J in. thick 
shown in II. If the joint is backed by a heavy steel plate, 
increasing thereby both its thermal capacity and conductivity, 
a higher current, in the neighborhood of 175 amp. to 200 amp., 
will be required for the same penetration. If a lap joint is 
made as in / and the same current used as in II, the flow of 
heat will be so rapid that poor fusion will result. By increas- 
ing the current to 225 amp., J, the desired penetration, as 
indicated by crater depth, will be obtained with the main- 
tenance of a high welding speed. 

Expansion and Contraction of Parent Metal. The welding 
operation necessarily raises the temperature of the metal adja- 
cent to the joint, producing strains in the structure if it does 
not expand and contract freely. This condition is particularly 
marked when welding a crack in a large sheet or plate. The 



58 ELECTRIC WELDING 

plate in the region of the welded section expands, the strains 
produced react on the cold metal at the end of the crack 
to open it further, with the result that as the welding proceeds 
the plate continues to open at a rate about equal to the welding 
speed. One inexperienced welder followed such an opening for 
7 ft. before adopting preventive measures. The simplest of 
these is to drill a hole at the end of the crack and follow an 
intermittent welding procedure which will maintain the plate 
at a low temperature. Under exceptional conditions, such as 
welding cracks in heavy cast-iron plates or cylinders, it is 
advisable to preheat and anneal the regions stressed. A second 
example is offered by the warping obtained on building up the 
diameter of a flanged shaft. The face of the flange adjacent 
to the shaft becomes hotter than that opposite, producing 
internal stresses which warp the flange to a mushroom shape. 
Preheating of the flange will prevent this. 

Contraction of Deposited Metal. The contraction of de- 
posited metal is the most frequent cause of residual stress in 
welds and distortion of the members welded. The magnitude 
of "loeked-in" stresses depends upon the welding procedure 
and the chemical constituents of parent and deposited metals. 
If the deposit is thoroughly annealed, practically no stress will 
remain. On adopting a welding sequence in which the joint 
is formed by running tiers of abutting layers, each newly 
applied layer will serve partly to anneal the metal in adjacent 
layers. If mild-steel plate, with less than 0.20 per cent carbon, 
is welded in this way, the locked-in stresses should be less than 
5,000 Ib. per square inch. With increase in carbon content the 
locked-in stresses will increase. If welded joints of high-carbon 
steels are not permitted to cool slowly, they will often fall 
apart when the joint is given a sharp blow. 

To illustrate this characteristic, the following exercises are 
suggested : 

Exercise 1 Deposit a layer 1 ft. long on a strip of steel 
about 8 /io in- thick, 1 / 2 in. wide, using 150 amp. direct current 
and a 5 / 32 -in. bare electrode. The longitudinal contraction of 
the deposit will bend the strip of metal as shown in Fig. 41. 

Exercise 2 IJeposit a layer of metal around the periphery 
of a wrought-iron tube. The contraction of the deposit will 
cause the tube to decrease in diameter. 



TRAINING ARC WELDERS 



59 



Exercise 3 Place two plates, in. thick, 2 in. wide, 6 in. 
long, -J in. apart, and deposit a layer of metal joining them 
together. The transverse contraction on cooling will pull the 
plates out of line. 











FIG. 41. Warping of the Parent Metal Caused by the Transverse Con- 
traction of the Deposited Layers. 



t&QLtfW&F DEPOSIT 




FIG. 42. Reduction of "Free Distance" Caused by Transverse Contraction. 

Illustrates the necessity of rigidly clamping the joint members, or of assembling 
them by an increasing distance from the end to be first welded, to equalize the 
movement caused by the contraction of the deposited metal, if the desired "free 
distance" is to be maintained throughout the welding operation. 

Exercise 4 If two plates, J in. thick, 6 in. wide and 6 in. 
long, spaced -J in., are welded by depositing a short layer 
extending in. from the one end, it will be found that when 



60 



ELECTRIC WELDING 



the deposit has cooled the resulting transverse contraction will 
not only warp the plates as in Exercise 3, but will also draw 
them together as shown in Fig. 42, thereby decreasing the free 
distance between plates. 

Welding Procedure. Satisfactory welds will be obtained 
only when the sections to be welded are properly scarfed or 
cut out and the surfaces on which the deposits arc formed 
cleaned before and during the welding operation. The scarfs 
may be machined or cut with a cold chisel or the carbon arc. 
The surfaces of the deposited layers may be cleaned with a 





FIG. 43. Welds Showing Poor and Good Fusion, 

Section through one-half of a welded joint showing poor fusion obtained at apex 
of V as the result of assembling the joint sections without a "free distance." Section 
through one-half of a welded joint showing excellent fusion obtained as a result 
of the use of a "free distance" of | in., thus permitting the operator to maintain a 
short arc when welding the bottom of the V. Failures of deep welds may be usually 
attributed to the use of too small a "free distance," low welding current, improper 
cleaning of scarf faces or incomplete slag flotation. 

chisel or wirebrush, although the iise of a sandblast is prefer- 
able. The joint sections should be separated by a free distance 
of about | in. in order that the bottom of the V may be acces- 
sible to the welder. 

The scarf angle and free distance vary inversely. Both 
are determined by the depth of the V. If the character of the 
work is such that it is not practicable to separate the joint 
sections, the V should be cut at the bottom to form a 90-dcg. 
angle, this angle being reduced to 60 deg. as the surface is 
approached; otherwise the scarf angle may be reduced along 
the entire length to 60 deg., excepting in the case of very deep 



TRAINING ART WKLDKKS (it 

welds. It is usual practice now to scarf plate welds to 60 dcg. 
and separate the sections i in. i'or V 's up to .1 in. in depth. 

At tin* left in Fig. 4,'i is shown the poor fusion obtained 
at the bottom of the V on welding a 1-in. square bar, scarfed 
6*0 dog., without the use of a free distance. At the right is 
shown the satisfactory union obtained with the use of free 
distance of i in. Whenever a butt joint is accessible to hori- 
zontal welding from both sides, it is preferable to scarf the 
sections to a double-bevel, douhle-Y joint. 

The choice of arc current is determined by the thermal 
conductivity and capacity of the joint as previously discussed, 
u convenient criterion being the depth of arc crater. The 
arc current selected should be of such a value that on welding 
the given sections the depth of the are crater or "bite," is 
never less than '/, in. 

Electrode Current Density. To maintain a uniform flow 
of the metal, neither too slow, which causes excessive penetra- 
tion, nor too fast, which produces excessive overlap, an elec- 
trode diameter should be chosen such that the current density 
is approximately 8,000 amp. per square inch. For* the usual 
sixes of bare wire available this corresponds to the following 
welding currents : 

At*- CttniMtt tAmp.) , Kli'ctrmlc 

Xnna! Mu&imum Minimum hiiunctcr cm,) 

:.!;*:> U7f urn ,VH> 



If covered electrodes are used, the direct -current rating for 
tlte wires should be decreased roughly to (50 per cent of these 
values. If hare wires an* used on alternating current, the 
rating should IN* increased from 20 to 40 per cent. 

The ttrst layer should thoroughly fuse* the apex of the V. 
Wherever possible inspect the reverse aide, as the deposited 
wefnl .should appear projecting through. Subsequent layers 
should he fused then to the preceding layers or to the scarfed 
fare, Thr Jinal surface should be from $ / M to */* in. above 
thai of th<* adjacent sect inns. This welt increases the strength 
of flu' joint or penuits the joint surface to be machined to a 
smooth finish. If the weld is to be mi-tight, the metal project- 



62 ELECTRIC WELDING 

ing through the abutting sections on the reverse side as a result 
of the first step in filling the section should be chipped out 
and the resulting groove filled with at least one layer of 
deposited metal. This extension of the procedure is frequently 
used in the welding of double-bevel joints where the joint is 
to have a "100 per cent" strength. 

If a vertical seam is to be welded, sufficient material should 
first be deposited to produce a shoulder so that the added 
metal may be applied on an almost horizontal surface to facili- 
tate the welding operation. 

If an overhead seam is to be welded, the operation is sim- 
plified by placing on the upper side of the joint a heavy steel 
plate covering the apex of the V. A shoulder is then formed 
by an initial deposit of metal, the operator continuing to add 
metal to the corner so produced and the vertical face of the 
shoulder. 

The considerations pointed out imder the section on thermal 
characteristics determine whether it is necessary to preheat 
and anneal the joint. The method used in filling the scarfed 
section is determined by the preference for either the rigid or 
non-rigid system. 

When using the rigid system both sections of the joint are 
clamped firmly to prevent either member from moving under 
the stresses produced by the expansion and contraction ob- 
tained during the welding operation. If a proper welding 
sequence is not followed, the accumulation of "locked-in" 
stresses on cooling may be sufficient to rupture the welded 
area. To minimize these stresses it is the usual practice to 
tack the plates together at the apex of the scarf with short 
deposits at about 1-ft. intervals, and then to deposit single 
layers in alternate gaps, each tier being completed before add- 
ing a second tier at any section. This procedure tends to 
maintain a low average temperature of the joint and plate, 
ther.eby decreasing the amount of expansion, while the deposi- 
tion of the metal in layers serves partly to anneal the metal 
beneath and materially reduce "locked-in" stresses. 

In the non-rigid system both members of the joint are free 
to move. To prevent the edges of the plate from overlapping 
or touching as shown in Fig. 42, the initial free distance is made 
great enough to equalize the movement of the plates caused 



TRAINING ARC WELDERS 63 

by the contraction of the hot deposited metal. On welding 
long seams of J-in. plate the contraction is limited by main- 
taining a spacing block 5 / lc i n - wide, approximately 1 ft. ahead 
of the welded section. With a "free distance " of in, the 
contraction stresses draw the plates together a distance of 
Y 1C in. This modification converts the non-rigid into a semi- 
rigid system. 

Inspection. No direct, non-destructive means are available 
for readily determining the strength and ductility of welds. 
A number of indirect methods, however, are in commercial 
use which give a fair measure of weld characteristics if intel- 
ligently applied. They consist in estimating the degree of 
fusion and porosity present by critically inspecting the surface 
of each layer and in noting the depth of liquid penetration 
through the completed section. 

In examining each layer the amount of oxide present, 
smoothness and regularity of the surface, its contour, freedom 
from porosity and depth of crater should be noted. After a 
little experience these observations will give the inspector a 
good indication of the manipulative ability of the welder and 
of the degree of fusion obtained, as discussed above. 

A succession of unfused zones will produce a leaky joint. 
These sections may be detected by flooding one surface of 
the joint with kerosene, using a retaining wall of putty, if 
necessary, as the liquid penetrates through, the linked areas 
and emerges to stain the opposite side. 

Brief Terminology. The following terms are used most 
frequently in arc welding: 

Free distance. The amount that the joint sections are separated before 
welding. 

Overlap. The area of deposited metal that is not fused to the parent 
metal. 

Parent metal. The original metal of the joint sections. 

Penetration. The depth to which the parent metal is melted by the arc 
gaged by the depth of the are crater. 

Recession. The distance between the original scarf line and the average 
depth of penetration parallel to this line obtained in the completed weld. 

He-entrant angle. The angle between the original surface of the parent 
metal and the overlapping, unfused deposit edge. 

ticarf. The chamfered surface of a joint. 

Tad: A short deposit, from % to 2 in. long, which serves to hold 
the sections of a joint in place. 



64 ELECTRIC WELDING 

Weaving. A semi -circular motion of the arc terminal to the right and 
left of the direction of deposition, which serves to increase the width of 
the deposit, decrease overlap and assist in slag flotation. 

Welt. The material extending beyond the surface of the weld shanks 
to reinforce the weld. 



QUESTIONS AND ANSWERS 

What does the welder's equipment consist of? 

Welding generator, electrode holder with cables, welding booth, helmet 
or shield, gauntlets, high shoes with bellows tongue, heavy clothing or 
leather apron, proper electrodes. 

What is the most important precaution the operator should observe? 

To protect his eyes and body from the radiant energy emitted by the 
arc. 

How is the operator prevented from drawing too long an arc after 
the electrode " freezes' 7 to the worK? 

By twisting the wrist sharply to the right or left, thereby shearing the 
fused area. 

What is the essential factor in securing the maintenance of the arc? 

The electrode should be advanced to the work at the rate at which it 
is being melted. 

What is the test of an operator's manipulative ability? 

He should be able to hold an arc no longer than J in., having a voltage 
across it less than twenty-five during the period required to deposit the 
metal from a 8 /3a~* n - diameter bare electrode, 12 in. long on 150 amp. 
direct current. 

What is meant by 1 1 free distance, 7 ' ' ' overlap, ? ' " parent metal, ' ' 
"penetration," "recession," "re-entrant angle," "scarf," "tack," 
"weaving" and "welt"? 

Given under "Terminology." 

What function does the are perform? 

It transforms electrical energy into thermal energy. 

What polarity should the welder use on welding all but thin sections 
with bare electrodes'? 

The pencil electrode should be negative. 

How may the amount of oxide formed be reduced to a minimum? 

By holding a short are and the use of electrodes containing a small 
quantity of carbon (0.18 per cent) and manganese (0.50 per cent). 

How may an operator determine the degree of fusion obtained (a) by 
inspecting the surface, (b) by inspecting the cross-section of deposit? 

(a) By examining the contour of the surface, noting the re-entrant 
angle and estimating the overlap ; observing the depth of crater and 
estimating the penetration. 

(b) By directly observing the depth of penetration of recession, the 
overlap and porosity or blow holes. 

What are the- factors in arc welding that determine the degree of 
fusion! 



TRAINING ARC WELDERS 65 

Arc current, arc length, electrode current density, electrode material, 
freedom of weld from oxides. 

How may a welder determine when he is using the proper welding 
current ? 

By the depth the arc melts the material welded. The crater should 
be not less than y 16 in. in depth. 

What is the most important thermal characteristic encountered in 
welding ? 

Contraction of the hot deposit. 

How may strains produced by this characteristic be minimized? 

By adopting a correct welding procedure, either non-rigid or rigid, 
which serves partly to anneal the metal and reduce "locked-in" stresses. 

What is the effect of holding too long an arc with the metallic electrode? 

The use of a long arc produces a poor deposit, due to insufficient 
penetration, and also produces a large amount of oxide which reduces both 
the strength and ductility of the joint. 

What size of bare electrodes corresponds to welding currents of 
approximately 225, 155, 100 and 60 amp. on welding with direct current! 

Sizes 3 / 16 , 5 / 32 , Ys an d Vsa in. respectively. 

How should joint sections be prepared for welding? 

The surfaces should be cleaned thoroughly and the faces of the joint 
scarfed to an angle of 60 to 90 degrees with the edges separated a free 
distance of approximately | in. in the rigid welding process, and an addi- 
tional Vic in. per foot from the point welded for each foot length when 
using the non-rigid system. 

What surface characteristics denote fusion? 

Surface porosity, amount of oxide coating, depth of arc crater, surface 
contour, compactness, regularity and re-entrant angles. 



CHAPTER V 
CARBON-ELECTRODE ARC WELDING AND CUTTING 

In the jLmeric&n Machinist of Sept. 9, 1920 ; 0. II. Escholz, 
research engineer of the Westinghouse Electric & Manufac- 
turing Co., dealt with the various phases of carbon arc welding 
and cutting as follows : 

Carbon or graphite electrode arc welding is the oldest of 
the electric fusion arc processes now in use. The original 
process consisted in drawing an arc between the parent metal 
and a carbon electrode in such a manner that the thermal 
energy developed at the metal crater fused together the edges 
of the joint members. This process was early modified by add- 
ing fused filling metal to the molten surface of the parent 
metal. 

The equipment now used consists of a direct-current arc- 
circuit possessing inherent means for stabilizing the carbon 
arc, a welding hood for the operator, an electrode holder that 
does not become uncomfortably hot in service and suitable 
clothing such as bellows-tongued shoes, gauntlets and apron of 
heavy material. 

"When arc currents of less than 200 amp. are used, or when 
a graphite arc process is employed intermittently with the 
metallic electrode process, the carbon-holding adapter shown 
in Fig. 44 may be used with the metallic electrode holder, the 
shank of the adapter being substituted for the metal electrode. 
With very high arc currents, 750 amp. or more, special holders 
should He constructed to protect the operator from the intense 
heat generated at the arc. Typical holders are shown in Figs. 
45 and 46. 

Electrodes. Although hard carbon was originally employed 
for the electrode material, experience has shown that a lower 
rate of electrode consumption as well as a softer weld may be 
obtained by substituting graphite electrodes. While both elec- 

66 



CARBON-ELECTRODE ARC WELDING AND CUTTING 67 

trodes have the same base and binder, the graphite electrode 
is baked at a sufficiently high temperature (2000 deg. C.) to 
graphitize the binder, thereby improving the bond and the 
homogeneity of the electrode. The graphite electrode is readily 





rc> 44. Adapters .for Using Carbons in Metallic-Electrode Holder 




FIG. 45. Metallic-Electrode Holder. 




FIG. 46. Carbon- or Graphite-Electrode Holder. 

distinguishable by its greasy "feel" and the characteristic 
streak it makes on paper. 

The diameter of the electrode is determined partly by the 
arc current. To fix the position of the carbon arc terminal, 



68 ELECTRIC WELDING 

thereby increasing arc stability and are control, all electrodes 
should be tapered. This precaution is particularly important 
when using low value of arc current or when maintaining an 
arc under conditions which cause distortion and instability. 
The following table gives electrode diameters in most common 
use with various arc currents: 

Amperes Diameter 

50 to 150 i in. tapered to in. 

150 to 300 g in. tapered to in. 

300 to 500 1 in. tapered to in. 

500 to 750 1 in. tapered to in. 

750 to 1000 H in. tapered to J in. 

Filler Material. A strong, sound weld can be obtained only 
by using for filler metal low-carbon, commercially pure iron 
rods having a diameter of | in. or | in., depending on the 
welding current used. Cast iron or manganese steel filler rods 
produce hard welds in which the fusion between the parent 
and added metals may be incomplete. Short rods of scrap 
metal, steel turnings, etc., are frequently made use of for filler 
metal when the purpose of the welder is merely to fill a hole 
as rapidly as possible. It should be understood that welds 
made with such metal are weak, contain many blowholes and 
are frequently too hard to machine. 

It is as difficult for the user of graphite arc processes as 
it is for the oxy-aeetylene welder to estimate the degree of 
fusion obtained between deposited and parent metals. There- 
fore the operator must follow conscientiously the correct pro- 
cedure, recognizing that the responsibility of executing a faulty 
weld rests solely with himself. He should, of course, have a 
working knowledge of metals, must be able to distinguish 
colors and possess a fair degree of muscular co-ordination, 
although the manipulative skill required is less than that neces- 
sitated by the metallic electrode process. 

For graphite arc welding employing a filler the correct 
posture is illustrated in Fig. 47. The filler rod is shown grasped 
by the left hand with the thumb uppermost. "When held in 
this position the welder may use the rod to brush off slag 
from the surface of molten metal or to advance the rod into 
the arc stream. 

The surfaces to be welded should be chipped clean. "Where 



CARBON-ELECTRODE ARC WELDING AND CUTTING 69 

they are scarfed the angle should be wide enough to enable the 
operator to draw an are from any point without danger of 
short-circiuting the are. It is the practice of some w r elders 
to remove sand and slag from the metal surfaces by fusing 
them with the aid of the arc and then striking the fluid mass 
with a ball-peen hammer. This method should be discouraged 
since both operator and nearby workmen may be seriously 
injured by the flying hot particles. 

Arc Manipulation. The arc is formed by withdrawing the 
graphite electrode from a clean surface of solid metal or from 
the end of the filler rod when it is held in contact with the 




j^io. 47. Correct Wcl<Vmg Position \vhcn Using Carbon Arc and a Filler Hod. 

parent metal. If the arc is formed from the surface of the 
deposited metal or from that of a molten area, slag particles 
may adhere to the end of the electrode, deflecting the arc and 
increasing tfic difficulty of manipulating it. 

By inclining the electrode approximately 15 deg. to the 
vertical the control of the position, direction and speed of the 
arc terminal is facilitated. When the electrode is held ver- 
tically irregularities in the direction and force of convection 
currents deflect the arc first to one side and then to another, 
causing a corresponding movement of the metal arc terminal. 
By inclining the graphite electrode the deflecting force is con- 
stant in direction, with the result that the electrode arc stream 



70 



ELECTRIC WELDING 



and arc terminal remain approximately in line, as shown in 
Pig. 48, and may then be moved in any direction or at any 
speed by a corresponding movement of the graphite electrode. 
Polarity. It is common knowledge that the positive 
terminal of a carbon arc is hotter and consumes more energy 
than the negative terminal. If the graphite electrode of the 
welding arc is made the positive terminal, energy will be use- 




-Arc Core, White 
-Arc Sfrea/77, Blue 



$&/- Arc Flame, 



PARENT METAL 
Positive 



Fie. 48. Position of Electrode and Characteristics of the Arc. 



lessly consumed and the resulting higher temperature will 
increase the loss of carbon through excessive oxidation and 
vaporization. Moreover, for reasons well known to those 
familiar with the phenomena of are formation, a very unstable 
arc is obtained with the iron parent metal functioning as the 
negative electrode. The graphite electrode should therefore 
always be connected to the negative terminal, reversal of 



CARBON-ELECTRODE ARC WELDING AND CUTTING 71 

polarity being detected when the arc is difficult to hold and 
when the carbon becomes excessively hot. 

Arc Length. Even when the graphite electrode serves as 
the negative arc terminal, its temperature is great enough to 
cause vaporization of a considerable quantity of carbon. If 
this carbon is permitted to be transferred to and absorbed 
by the fluid metal, a hard weld will result. To insure a soft 
metal practically all of the volatilized carbon should be oxid- 
ized. This may be accomplished by regulating the arc length 
so that atmospheric oxygen will have ample time to diffuse 
through the arc stream and combine with all of the carbon 
present. The correct arc length is dependent upon the welding 
current and the degree of confinement of the arc. Since the 
arc diameter varies as the square root of the current the arc 
length should be increased in proportion to the square root of 
the current. It is also obvious that when an arc is drawn 
from a flat, open surface the vaporized carbon is more acces- 
sible to the atmospheric gases than when it is inclosed by the 
walls of a blowhole. This means that to secure the same amount 
of oxidized carbon under both conditions the confined arc 
should be the longer. Many welders are not familiar with 
this phenomenon, with the result that metal deposited in holes 
or corners appears to be inexplicably hard. 

The length of a 250-amp. arc should not be less than % in. 
and that for a 500-amp. arc should not be less than 5 in. when 
drawing the arc from a flat surface. The maintenance of 
excessive arc lengths causes the diffusion, through convection 
currents, of the protecting envelope of carbon dioxide, with 
the result that the exposed hot metal is rapidly oxidized or 
"burned." For most purposes a 250-amp. arc should not 
exceed a length of 1 in. and the length of a 500-amp. arc should 
not exceed 1-J in. In view of the large variation permissible, 
the welder should be able to maintain an arc length which 
assures a soft weld metal with but little slag content. 

The arc serves to transform electrical energy into thermal 
energy. The energy developed at the metal terminal or arc 
crater is utilized to melt the parent metal, while that generated 
in the arc stream serves to melt the filling material. If the 
molten filler is not properly guided and, as a consequence, 
overruns the fused parent metal, a poor weld will result. This 



72 



ELECTRIC WELDING 



process necessitates, therefore, a constant observation of the 
distribution of the fused metals as well as a proper control 
of the direction of flow and speed of deposition of the filling 
metal. 

There are two methods in use for adding the filler with a 




FIG. 49. Starting to Build Up a Surface. 

minimum overlap. One is called the "puddling" process. It, 
consists in melting a small area of the parent metal, thrusting 
the end of the filler rod into the arc stream, where a small 
section is melted or cut off, withdrawing the rod and fusing 
the added material with the molten parent metal by imparting 




FlG. 50. Building-Up Process Nearly Completed. 

a rotary motion to the arc. This puddling of the metals serves 
also to float slag and oxidized material to the edge of the 
fused area, where they may be brushed or chipped off. 

The rapid building up of a surface by this method is shown 
in Fig. 49. The short sections of filler rod were welded to 



CARBON-ELECTRODE ARC WELDING AND CUTTING 73 

the sides of the easting in order to prevent the molten material 
from overflowing and to indicate the required height of the 
addition. The appearance of the nearly completed "fill" is 
shown in Fig. 50. One side of the added metal is lower than 
the others to facilitate the floating off of the slag, some of 



tw^ 1*1 ... \ ' & .'A, ' r ^ * t * 1 ,. .sf _^t idfr * i 




. 51. Section Through a Built-Up Weld. 




FIG. 52. Method of Depositing Pilling Material in Layers. 

which may be observed adhering to the edge of the plate. 
Fig. 51 shows a section through a weld produced in this man- 
ner, the continuous line indicating the zone of fusion and the 
broken line the boundary of crystal structural change produced 
by the temperature cycle through which the parent metal has 
passed as a result of the absorption of the arc energy. 



74 



ELECTRIC WELDING 



Some iisers of tins method advocate puddling short sections 
of the filler rod, 1 to 3 in. in length, with the parent metal. 
"Where this is done, the filler may be incompletely fused and 
therefore not welded to the surface of the parent metal 

In the second method the filler material is deposited in 




FIG. 53. Layers of Deposits Smoothed Over. 







FIG. 54. Fused Ends of Filler Kods. 

layers, as shown in Figs. 52 and 53, the deposits being similar 
to those obtained with the metallic electrode process but wider 
and higher. In these examples a welding current of 250 amp. 
with a filling rod | in. in dia. were used. This method simply 
requires the operator to feed the filling rod continuously into 
the arc stream so that the molten filler deposits on the area 



CARBON-KLKCTKODK ARC WKLDING AND CUTTING 75 

of parent metal fxised by the are terminal while the are, travels 
across the surface. If! the end ol! the rod is moved forward 
while resting oil the surface of the newly deposited metal, 




KKJ. 55. Showing the Fusion of Puivnt MHnl an! I-'itur l*:iy*'r.s. 

most of the slag produced by the oxidation of the hot metal 
is floated to thi k sides of the deposit, when* if may ir brushed 
or ehipped off. 

The appearance of fused filler rod ends when eorreetly 
nianiptilated is shown in Fijj. T>4, Slag luny be tb,served .still 









Fw. rjO.-'l'*IfiK'tl Kil^t'fi Wfl*linl with 



Arc, 



adhering to the l^oflom of mti* of the rods. Th<* ftisiou l'lweeii 

parent itnd added met it! is shown in Fig. f5. Four luytrs of 
added metal are shown at tin* upper wurfnr*', 

To reinuve slajjf * j r improve tlt- appearance of the tte 



76 ELECTRIC WELDING 

the surface of the added metal may be remelted by running 
the arc terminal over it, provided "burning" and hardening 
of the metal is avoided. Figs. 52 and 53 illustrate plainly the 
appearance of deposits before and after the surfacing operation. 

The expedient of hammering or swaging the hot deposited 
metal is frequently resorted to where a refinement in the struc- 
ture of the crystal grains is desirable. 

Flanged Seam Welding. Fig. 56 illustrates a useful appli- 
cation of the original carbon-arc process wherein no filler metal 
is used, the metal arc terminal serving to melt together the 
flanged edges. 

This process is easily performed. To obtain adequate fusion 
the arc current selected should have such a value that the 
metal-arc crater nearly spans the edges of the seam. To assure 
the maintenance of a stable arc a small, tapered electrode 
should be employed, the diameter of the electrode end remain- 
ing less than -J-in. during use. 

This graphite arc process is used occasionally to form butt 
and lap welds by melting together the sides of the joint without 
the use of filler metal. Examination of sections through joints 
made in this manner reveals that the weld is very shallow and 
therefore weak. 

Welding of Non-Ferrous Metals. Copper and bronzes have 
been successfully welded with the graphite arc when employ- 
ing a bronze filler rod low in tin and zinc and high in phos- 
phorous, at least 0.25 per cent. The best filler material for 
the various analyses of parent metals has not been determined, 
but it is recognized that the presence of some deoxidizing agent 
such as phosphorus is necessary in order to insure sound welds 
free from oxide and blowholes. Since copper and its alloys 
have a high thermal capacity and conductivity, preheating of 
the structure facilitates the fusion of the joint surfaces. The 
grain of the completed weld may be refined by subjecting the 
metal to a suitable mechanical working and temperature cycle. 

Low-melting-point metals such as lead may be welded by 
holding the graphite electrode in contact with the surfaces to 
be fused without drawing an arc, the current value used being 
sufficient to heat the end of the carbon to incandescence. The 
hot electrode tip may also be used to melt the filler rod into 
the molten parent metal 



CARBON-ELECTRODE ARC WELDING AND CUTTING 77 

Application. The graphite arc processes may be used for 
the following purposes: 

(1) Welding of cast steel and non-ferrous metals. 

(2) Cutting of cast-iron and cast-steel risers and fins and 
non-ferrous metals. 

(3) Eapid deposition of metal to build up a surface or fill 
in shrinkage cavities, cracks, blowholes and sand pockets where 
strength is of minor importance. 

(4) Fusion of standing seams. 

(5) Melting and cutting- of scrap metal. 

(6) Remelting of a surface to improve its appearance or fit. 




FIG. 57. Typical Carbon-Electrode Cuts in -In. Ship Plate. 



(7) Preheating of a metal structure to facilitate the welding 
operation, to reduce locked-in stresses or to alter some 
dimension. 

(8) Deposition of hard metal or the hardening of a surface 
by the inclusion of vaporized carbon, such as rails, frogs and 
wheel treads. 

(9) Automatic cutting and welding of sheet metal. 
Cutting. The manipulation of the cutting arc is exceed- 

ingly simple, the operator merely advancing the arc terminal 
over the section to be ctit at a rate equal to that at which 
the molten metal flows from the cut. The cutting speed in- 



78 ELECTRIC WELDING 

creases with the value of arc current used. The width of the 
cut increases with the are diameter and therefore as the square 
root of the arc current. Fig. 57 shows the appearance of cuts 
made in ship steel plate % in. thick. The following data apply 
in this case : 

Position of Cut Amp. Width, in. Length, in. Time, rain. 

Upper 250 0.5 8 2 

Lower 650 0.8 8 1 

Before cutting this plate the welder outlined the desired 
course of the cut by a series of prick-punch marks. 

When cutting deeper than 4 in. the electrode should not 
come in contact with the walls of the cut and thereby short- 
circuit the arc. 

This process may be used for cutting both ferrous and non- 
ferrous metals. It has found a particularly useful field in the 
cutting of cast iron. It is often used for the " burning' ' out 
of blast-furnace tap holes and the melting or cutting of iron 
frozen in such furnaces. 

CUTTING METALS 

The accompanying charts illustrate the application of the 
carbon electrode cutting process with a current value of 350 
to 800 amperes, depending on the thickness of the metal and 
the speed of cutting desired. A moderate cutting speed is 
obtained at a small operating expense, adapting it particularly 
for use in foundries for cutting off risers, sink heads, for cut- 
ting up scrap, and general work of this nature where a smooth 
finish cut is not essential. 

The cross section of these risers, etc., is frequently of con- 
siderable area, but by the iisc of the proper current value, 
they may be readily removed. 

Table IV shows the results obtained from tests in cutting 
steel plate with the electric arc. The curves show the rate 
of cutting cast iron sections of various shapes. Fig. 58 shows 
the rate of cutting cast iron plates. Fig. 59 circular cross 
sections, and Fig. 60 square blocks. The curves are based on 
data secured through an extensive series of observations. 



CARBON-ELECTRODE ARC WELDING AND CUTTING 79 





\ 








\ 






I 










s 


\ 








) 






\ 










~~ b 

.5 




\ 








\ 




\ 


< 








-3 




\ 


fcJrfV, 












V, 








B J 

c 






^ 


OrV, 






^"^* 


^ 


Jnchcg] 


*^ 


fefe 




^2 
& 


























1 































S 1 


.0 1 

1 


5 2 

I 


Kches 


Sut p 


ir Minu 


Vc 











8. Bate of Cutting Cast Iron Plates. 



















X 


x**^ 














S 


x" 
















x 
















/ 


x 












^ 




/ 
















_c~8 


/ 


/ 


















/ 


















Q 


/ 








































1 


o ; 


zo a 


4 

|.Min 


5 

jtcs 


t 


V 

1 


o t 






59. Kate of Cutting Cast Iron of Circular Cross Section, 



-12 
10 

I*" 1 

I-' 



40 70 90 100 1 120 130 

| | I itanutj. I 1 1 I I L 



60. Bate of Cutting Cast Iron Square Blocks. 



80 ELECTRIC WELDING 

TABLE IT. CUTTING STEEL PLATES WITH THE CARBON ARC 



Thickness 


Current 


Speed Minutes 




in Inches 


in Amps. 


Per Ft. 


Kw.-Hrs. Per Ft. 


1 


400 


.50 


.312 


J 


400 


1.20 


.75 


S 


400 


2.14 


1.34 


2 


400 


3.00 


1.88 


1 


600 


3.75 


3.50 


11 


600 


4.32 


4.10 


2 


600 


6.75 


6.30 


4 


600 


16.90 


15.50 


6 


800 


20.00 


36.20 


8 


800 


40.50 


50.00 


10 


800 


59.00 


74.00 


12 


800 


65.00 


82.00 



CHAPTER VI 
AEG WELDING PROCEDURE 

It is presumed that the welder has a fair knowledge of 
the different processes of both carbon and metallic arc weld- 
ing, gained from reading the previous chapters or from actual 
experience. However, we will recapitulate to some extent 
in order to make everything as clear as possible. Then we shall 
give some examples of the proper procedure in making welds 
of various kinds. For the descriptions and drawings we arc 
principally indebted to the Westinghouse Electric and Manu- 
facturing Co., the Lincoln Electric Co., and the Wilson Welder 
and Metals Co. 

In order to prepare the metal for a satisfactory weld, the 
entire surfaces to be welded must be made readily accessible 
to the deposit of the new metal which, is to be added. In 
addition, it is very essential that the surfaces arc free from 
dirt, grease, sand, rust or other foreign matter. For this 
service, a sandblast, metal wire brush, or cold chisel are recom- 
mended. 

During the past few years great progress has been made 
in the improvement of steels by the proper correlation of 
heat treatment and chemical composition. The characteristics 
of high-carbon and alloy steels, particularly, have been radically 
improved. However, no amount of heat treatment will appre- 
ciably improve or change the characteristics of medium and 
low-carbon steels which comprise the greatest field of applica- 
tion for arc welding. Furthermore, the metal usually deposited 
by the arc is a low-carbon, steel often approaching commercially 
pure iron. -It must be evident therefore that the changes of 
steel structure due to the arc-welding process will not be 
appreciable and also that any subseqiicnt heat treatment of 
the medium- or mild-steel material will not result in improve- 
ments commensurate with the cost. 

81 



82 ELECTRIC WELDING 

Pre-heating of medium and mild steel before applying the 
arc is not necessary and will only enable the operator to make 
a weld with a lesser value of current. 

Cast-iron welds must be annealed before machining other 
than grinding is done in the welded sections. This is necessary 
because at the boundary between the original cast iron and 
the deposited metal there will be formed a zone of hard, high- 
carbon steel produced by the union of carbon (from the cast 
iron) with the iron filler. This material is chilled quite sud- 
denly after the weld is made by the dissipation of the heat 
into the surrounding east iron which is usually at a com- 
paratively low temperature. 

Although it is not absolutely necessary to prc-hcat cast iron 
previous to arc welding, this is done in some instances to 
produce a partial annealing of the finished weld. The pre- 
heating operation will raise the temperature of a large portion 
of the easting. "When the weld is completed, the heat in the 
casting will flow into the welded section, thereby reducing the 
rate of cooling. 

Arc Length. The maintenance of the proper arc length for 
the metallic electrode process is very important. With a long 
are an extended surface of the work is covered probably caused 
by air drafts with the result that there is only a thin deposit 
of the new metal with poor fusion. If, however, the arc is 
maintained short, much better fusion is obtained, the now 
metal will be confined to a smaller area, and the burning and 
porosity of the fused metal will be reduced by the greater 
protection from atmospheric oxygen afforded by the envelop- 
ing inert gases. With increase in arc length, the flame becomes 
harder to control, so that it is impossible to adequately protect 
the deposited metal from oxidation. 

The arc length should be uniform and just as short as it is 
possible for a good welder to maintain it. Under good normal 
conditions the arc length is such that the arc voltage never 
exceeds 25 volts and the best results are obtained between 
18 an<? 22 volts. For an arc of 175 amp. the actual gap will 
be aboat -J inch. 

Manipulation of the Arc. The arc is established by touch- 
ing the electrode to the work, and drawing it away to ap- 
proximately -J in., in the case of the metallic electrode. This 



ARC WELDING PROCEDURE 83 

is best done by a dragging touch with the electrode slightly 
out of vertical. The electrode is then held approximately at 
right angles to the surface of the work, as the tendency is 
for the heat to go straight from the end of the electrode. This 
assures the fusing of the work, provided the proper current 
and arc length have been uniformly maintained. 

A slight semicircular motion of the electrode, which at the 
same time is moved along the groove, will tend to float the 
slag to the top better than if the electrode is moved along a 
straight line in one continuous direction and the best results 
are obtained when the welding progresses in an upward direc- 
tion. It is necessary in making a good weld to "bite" into 
the work to create a perfect fusion along the edges of the 
weld, while the movement of the electrode is necessary for the 
removal of any mechanical impurities that may be deposited. 
It is the practice to collect the slag about a nucleus by this 




c 

FIG. 61. Diagram Illustrating Filling Sequence. 

rotary movement and then float it to the edge of the weld. 
If this cannot be done, the slag is removed by chipping or 
brushing with a wire brush. 

Filling Sequence. "When making a long seam between 
plates, the operator is always confronted with the problem 
of expansion and contraction which cause the plates to warp 
and produce internal strains in both plates and deposited 
material. 

The method of welding two plates together is shown in 
Fig. 61. The plates are prepared for welding as previously 
described, and the arc is started at the point A. The welding 
then progresses to the point B, joining the edges together, to 
point D and back to A. This procedure is carried on with 
the first layer filling in a space of 6 or 8 in. in length, after- 
ward returning for the additional layers necessary to fill the 
groove. This method allows the entire electrode to be deposited 
without breaking the arc, and the thin edges of the work are 



84 



ELECTRIC WELDING 



not fused away as might be the case if the operator should 
endeavor to join these edges by moving- the electrode in one 
continuous direction. This method also prevents too rapid 
chilling with consequent local strains adjacent to the weld. 

When making a long seam weld, for example, a butt weld 
between two plates, the two pieces of metal will warp and have 
their relative positions distorted during the welding process, 
unless the proper method is used. 

A method was devised and has been successfully put into 
operation by E. Wanamaker and H. R. Pennington, of the 
Chicago, Rock Island and Pacific R.R. By their method the 



FIG. 62. Diagram Jlhistrating Back-Step Method. 

plates are fastened together by light tack wolds about 8 in. 
apart along the whole seam. The operator then makes a com- 
plete weld between the first two tacks as described in the 
preceding paragraph, and, skipping three spaces, welds between 
the fifth and sixth tacks and so on until the end of the seam 
is reached. This skipping process is repeated by starting be- 
tween the second and third tacks and so on until the complete 
seam is welded. The adoption of this method permits the heat, 
in a restricted area, to be dissipated and radiated before addi- 
tional welding is performed near that area. Thus the weld is 
made on comparatively cool sections of the plates which keeps 
the expansion at a minimum. 



ARC . WELDING PROCEDURE 85 

Another method very similar to the preceding one, is known 
the back-step method, Fig. 62, in which the weld is performed 
sections as in the skipping process. After the pieces are 
l ,ked at intervals of 6 in. or less for short seams, the are 
applied at the second tack and the groove welded back 
mplete to the first tack. Work is then begun at the third 
ik and the weld carried back to the second tack, practically 
mpleting that section. Each section is finished before start- 
% the next. 

Fig. 63 shows the procedure of welding in a square sheet 
patch. Work is started at A and carried to B completely 
aiding the seam. In order that work may next be started 
the coolest point, the bottom seam is completed starting 
D, finishing' at C. The next seam is A to D, starting at A. 



Pro. fi.'i. Diagram Illustrating Square Patch Method. 



D 



u> last scam is finished, starting at B, and completing the 
:>ld at 0. 

Alternating-Current Arc Welding. Direct current has been 
i<d for arc welding because of the fact that it possesses cer- 
iri inherent advantages that make it especially adaptable for 
is class of work. However, the use of alternating current 
r arc welding has found a number of advocates. 

When employing this form of energy, use is made of a trans- 
Tin or to reduce the distribution voltage to that suitable for 
)plie,atkm to the weld. 

Inasmuch as the arc voltage is obtained directly from the. 
stribution mains through a transformer, the theoretical effi- 
oney is high compared with the direct-current process which 
squires the introduction of a motor-generator or resistor or 



86 ELECTRIC WELDING 

both. The efficiency of the a.c. equipments now on the market 
ranges from 60 to 80 per cent. The transformer, however, 
is designed to have a large leakage reactance so as to furnish 
stability to the arc, which very materially reduces its efficiency 
when compared with that of the standard distribution trans- 
former used by lighting companies. 

It is difficult to maintain the alternating arc when using 
a bare electrode though this difficulty is somewhat relieved 
when use is made of a coated electrode. 

Quasi Arc Welding 1 . The electrodes used in quasi arc weld- 
ing are made by the Quasi Arc "Weldtrode Co., Brooklyn, N. 
Y., and are known as "wekltrodes. " A mild-steel wire is used 
with a very small aluminum wire running lengthwise of it. 
Around the two is wrapped asbestos thread. This asbestos 
thread is held on by dipping the combination into something 
similar to waterglass. Either a.e. or d.e. may be used, at a 
pressure of about 105 volts, with a suitable resistance, for 
regulating the current. The company's directions and claims 
for this process are: "The bared end of the weldtrode, held in 
a suitable holder, is connected to one pole of the current supply 
by means of a flexible cable, the return wire being connected 
to the work. In the case of welding small articles, the work 
is laid on an iron plate or bench to which the return wire is 
connected. Electrical contact is made by touching the work 
with the end of the weldtrode held vertically, thus allowing 
current to pass and an arc to form. The weldtrode, still kept 
in contact with the work, is then dropped to an angle, and a 
quasi-arc will be formed owing to the fact that the special 
covering passes into the igneous state, and as a secondary 
conductor maintains electrical connection between the work 
and the metallic core of the weldtrode. The action once started, 
the weldtrode melts at a uniform rate so long as it remains 
in contact, and leaves a seam of metal fused into the work. 
The covering material of the weldtrode, acting as a slag, floats 
and spreads over the surface of the weld as it is formed. The 
fused metal, being entirely covered by the slag, is protected 
from oxidation. TRe slag covering is readily chipped or 
brushed off when the weld cools, leaving a bright clean metallic 
surface. In welding do not draw the weldtrode along the 
seam, as it is burning away all the time, and therefore it is 



ARC WELDING PROCEDURE 



87 



only necessary to feed it down, but do this with a slightly 
lateral movement, so as to spread the heat and deposited metal 
equally to both sides of the joint. Care must be taken to keep 
feeding down at the same rate as the weldtrode is melting. 
On no account draw the weldtrode away from the work to 
make a continuous arc as this will result in putting down 
bad metal. The aim should be to keep the point of the weld- 



1%%% Ifes^ 

Before 



After 




After 




After 



Before 



After 




After 




After 



Before 




After 
.After 
FIG. 64. Typical Examples of Prepared and Finished Work. 

trode just in the molten slag by the feel of the covering just 
rubbing on the work. By closely observing the operation, the 
molten metal can easily be distinguished from the molten slag, 
the metal being dull red and the slag very bright red. " 

The weldtrodes are supplied ready for us<5 in standard 
lengths of 18 in., and of various diameters, according to the 
size and nature of the work for which they are required. 



88 



ELECTRIC WELDING 



Typical Examples of Arc Welding. The examples of weld- 
ing shown in Figs. 64, 65 and 66 are taken from, the manual 
issued by the Wilson "Welder and Metals Co. They will be 
found very useful as a guide for all sorts of work. Fig. 64 



Before 



After 



Before 




After 




After 



After 




After 



After 



After 



1 "" 

? 


': 
isrswtJSrT'l 


!. 





Before 



After 





Before 




After 



Before 





1 

i 


( L___ 


L 



After 



FIG. 65, Examples of Tube Work. 



shows miscellaneous plate or sheet jobs, Fig. 65 shows tube 
jobs, while Pig." 66 gives examples of locomotive-frame and 
boiler-tube welding. 

As a basis for various welding calculations the following 
data will be found of use: On straight-away welding the 



ARC WELDING PROCEDURE 



89 



ordinary operator with helper will actually weld about 75 per 
cent of the time. 

The average results of a vast amount of data show that an 




Great care must be exerciser in the preparation of 
the frames for welding, and thai Me proper hecrt value 
and welding metals ~be employed for the (.afferent 
character or material in the frames to be we/dec/ 



Copper- 
Ferrule 




>T i 

r, 1 Flue in Place 

and Expanded 




\ Before 
I Weld ing 



[ :r ] Before T 1 Before I "^1 
\._ jWelding ^ j Welding j 



Before 
Welding 




in woteling flues by the Electric Arc process, the flue sheet and flues 
must in all cases be entirely from scale, rust or other fo> ' 



After 
,^J Weld ing 

7ae sheet an& 

7/tr examples shawr, represent ~m&fiiods that have given good results 
i>u, tnciv l- mncri ^ meet different conditions. We proper heat value 
.0 ernp/cr ~inj ntnotmr ef me.hil h apply must t^ detcr/fiirtec/ in *?<;// cose. 

FIG. (>6. Examples of Electric Welding of Locomotive Frames and. 
Boiler Tubes. 

operator can deposit about 1.8 Ib. of metal per hour. This 
rate depends largely upon whether the work is done out in 
the open or in a special place provided in the shop. For 
outside work such as on boats, an operator will not average 



90 ' ELECTRIC WELDING 

in general more than 1.2 Jb. per .hour, while in the shop the 
same operator could easily deposit the 1.8 Ib. stated above. 
This loss in speed for outside work is brought about largely 
by the cooling action of the air and also somewhat by the 
added inconvenience to the operator. The value of pounds 
per hour given above is based on the assumption that the work 
has been lined up and is ready for welding. On the average 
70 per cent of the weight of electrodes is deposited in the 
weld, 12 per cent is burned or vaporized and the remainder 
18 per cent is wasted as short ends. 

Other figures prepared by the Electric Welding Committee 
show the possible cost of a fillet weld on a -J-in. plate, using 
a motor generator set and bare electrodes to be as follows: 

Average speed of welding on continuous straight away work 5 ft. per hour 

Amount of metal deposited per running foot 6 Ib. 

Current 150 amps, at 20 volts rr 3 kilowatts. 

Motor generator eff. 50 per cent = 6 kw. -j- 5 equals 1.2 k.w.h. per 1 ft. rim 

1.2 k.w.h. at 3 cents per k.w.h. equals 3.0 cents per ft. 

Oost. of electi'ode 10 cents per pound and allowing 

for waste ends, etc., equals 7.2 cents per ft. 

Labor at 65 cents per hour equals 13.00 cents per ft. 

23.8 cents per ft. 

Suggestions for the Design of Welded Joints. From an 
engineering point of view, every metallic joint whether it be 
. riveted, bolted or welded, is designed to withstand a perfectly 
definite kind and amount of stress. An example of this is the 
longitudinal seam in the shell, of a horizontal fire-tube riveted 
boiler. This joint is designed for tension and steam tightness 
only and will not stand even a small amount of transverse 
bending stress without failure by leaking. If a joint performs 
the function for which it was designed and no more, its designer 
has fulfilled his responsibilities and it is a good joint 
economically. Regardless of how the joint is made the design 
of joint which costs the least to make and which at the same 
time performs the functions required of it, with a reasonable 
factor of safety, is the best joint. 

The limitations of the several kinds of mechanical and 
welded joints should be thoroughly understood. 

A bolted joint is expensive, is difficult to make steam- or 
water-pressure tight, but has the distinguishing advantage that 



ARC WELDING PROCEDURE 91 

it can be disassembled without destruction. Bolted joints which 
are as strong as the pieces bolted together are usually imprac- 
ticable, owing to their bulk. 

Riveted joints are less expensive to make than bolted joints 
but cannot be disassembled without destruction to the rivets. 
A riveted joint, subject to bending stress sufficient to produce 
appreciable deformation, will not remain steam- or water- 
pressure tight. Riveted joints can never be made as strong 
as the original sections because of the metal punched out to 
form the rivet holes. 

There is no elasticity in either riveted, bolted or fusion- 
welded joints which must remain steam- or water-pressure 
tight. Excess material is required in the jointed sections of 
bolted or riveted joints, owing to the weakness of the joints. 

Fusion-welded joints have as a limit of tensile strength 
the tensile strength of cast metal of a composition identical 
to that of the joined pieces. The limit of the allowable 
bending stress is also set by the properties of cast metal of 
the same composition as that of the joined pieces. The reason 
for this limitation is that on the margin of a fusion weld 
adjacent to the pieces joined, the metal of the pieces was heated 
and cooled without change of composition. Whatever proper- 
tics the original metal had, due to heat or mechanical treatment, 
are removed by this action, which invariably occurs in a fusion 
weld. Regardless of what physical properties of the metal used 
to form the joint may be, the strength or ability to resist 
bending of the joint, as a whole, cannot exceed the correspond- 
ing properties of this metal in the margin of the weld. Thus, 
assuming that a fusion weld be made in boiler plate, having 
a tensile strength of 62,000 pounds. Assume that nickel-steel, 
having a tensile strength of 85,000 Ib. be used to build up the 
joint. No advantage is gained by the excess 23,000 Ib. tensile 
strength of the nickel-steel of the joint since the joint will 
fail at a point close to 62,000 Ib. If appreciable bending stress 
be applied to the joint it will fail in the margin referred to. 

The elastic limit of the built-in metal is the same as its 
ultimate strength for all practical purposes, but the ultimate 
strength is above the elastic limit of the joined sections in 
commercial structures. 

In spite of the limitations of the fusion-welded joint it is 



92 ELECTRIC WELDING 

possible and practicable to build up a joint in commercial steel 
which will successfully resist any stress which will be en- 
countered in commercial work. 

The fundamental factor in the strength of a welded joint 
is the strength of the material added by the welding process. 
This factor depends upon the nature of the stress applied. 
The metal added by the welding process, when subject to 
tension, can be relied on in commercial practice to give a ten- 
sile strength of 45,000 Ib. per square inch. This is an average 
condition; assuming that the metal added is mild steel and 
that the operation is properly done, the metal will have ap- 
proximately the same strength in compression as in tension. 
When a torsional stress is applied to a welded joint the 
resultant stress is produced by a combination of bending, ten- 
sion and compression, as well as shear. The resistance of the 
metal to shear may be figured at 8 / 10 its resistance to tensile 
stress. The metal added by the welding process, with the 
present development in the art of welding, will stand very 
little bending stress. A fusion-welded joint made by the elec- 
tric-arc process must be made stiver than the adjacent sections 
in order that the bending stress shall not come in the joint. 
An electric weld, when properly made, will be steam- and 
water-pressure tight so long as bending of members of the 
structure does not produce failure of the welded joint. 

Little is known at the present time in regard to the resist- 
ance of an electrically welded joint to dynamic stress, but 
there is reason to believe that the resistance to this kind of 
stress is low. However, owing to the fact that in most struc- 
tures there is an opportunity for the members of the structure 
to flex and reduce the strain upon the weld, this inherent weak- 
ness of the welded joint does not interfere seriously with its 
usefulness. 

A few tests have been made of high-frequency alternating 
stresses and it has been found that using the ordinary wire 
electrode the welded joint fails at a comparatively small num- 
ber of alternations. This is of little importance in most struc- 
tures since high-frequency alternating stress is not often 
encountered. 

Stresses in Joints. The accompanying cuts show a number 
of typical joints and the arrows indicate the stresses brought 



ARC WELDING PROCEDURE 




p IG> (37. Joints Designed to Overcome Certain Stresses. 



94 



ELECTRIC WELDING 



to bear on them. The proper way to weld each example is 
plainly shown. 

In A, Pig. 67, it will be noted that a reinforcing plate is 
welded to the joint to make the joint sufficiently stiff to throw 
the bending outside the weld. 

B shows a joint in straight tension. Since no transverse 
stress occurs the heavy reinforcing of A is not required. Just 
enough reinforcing is given the joint to make up for the defi- 
ciency in tensile strength of the metal of the weld. 

G shows another method of building up a joint that is in 




FIG-. 68. Plate and Angle Construction. 



straight tension. It Should be noted that in both B and C 
as much reinforcing is placed on one side of a center line 
through the plates as is placed on the other. 

The original form of lap joint such as is used in riveting 
is shown at D. The method shown for welding this joint is 
the only method which can be used. It cannot be recommended 
because such a joint, when in straight tension, tends to bring 
the center line of the plate into coincidence with the center 
line of the stress. In so doing an excessive stress is placed on 
the welded material. 

E shows the construction used in certain large tanks where 



ARC WELDING PROCEDURE 



95 



a flanged head is backed into a cylindrical shell. The principal 
stress to be resisted by the welded joint is that tending to 
push the head out of the shell. The welding process indicated 
in the figure will successfully do this. Owing to the friction 
between the weld and the shell, the outer weld would be suffi- 
cient to hold the weld in place for ordinary pressure. For 
higher pressures the inside weld should be made in addition. 





Pic. (59. Pipe Heading and Firebox Sheet Work. 

F and G show another method of welding a flanged head 
to the cylindrical shell. These methods are preferable to the 
method indicated in. E. G represents the recommended 
practice, 

Pig. 68 shows a plate and angle structure which might 
be used in ship construction. The particular feature to notice 
in the welding practice indicated, is that* the vertical plates 
do not reach the entire 1 distance between the horizontal plates. 



96 ELECTRIC WELDING 

This is merely a method of eliminating difficulties in welding 
the plates to the angle. 

A in Fig. 69 shows a method of welding a head into a 
cylindrical pipe. The thickness of the head should be ap- 
proximately twice the thickness of the wall of the pipe. The 
extra thickness plate is to gain sufficient stiffness in the head 
to make the stress on the welded material, purely shear. The 
pressure from the inside tends to make the head assume a 
hemispherical shape. This would place a bending stress on 
the welded material if the head were thin enough to give at 
the proper pressure. 

B shows a method of welding a crack in a fire-box sheet. 
The thin plate backing introduced at the weld makes the 
operation very much easier for the operator and produces the 
reinforcing of the water side of the fire-box sheet which is 
most desirable. 

INSPECTION OF METALLIC ELECTRODE ARC WELDS 

Determining the character of welded joints is of prime 
importance, says 0. S. Escholz, and the lack of a satisfactory 
method, more than any other factor, has been responsible for 
the hesitancy among engineers of the extensive adoption of 
arc welding. To overcome this prejudice it is desirable to 
shape our rapidly accumulating knowledge of operation into 
an acceptable method of inspection. 

Manufactured apparatus is practically all accepted on the 
basis of complying with a process specification rigidly enforced 
in conjunction with the successful reaction to certain tests 
applied to the finished product.. Riveting impairs the strength 
of the joined plates, yet with a proper layout and intelligent 
inspection the completed structure possesses certain definite 
characteristics which do not require further verification. The 
inspector of a finished concrete structure is practically help- 
less, and the weakest sort of construction may bo con coal od 
by a sound surface. "With careful supervision, however, the 
physical properties of the completed structure can be reliably 
gaged to the extent that the use of concrete is justified even 
in ship construction. With this in view, electric arc welding 
is susceptible to evfcn better control than obtain in either of 
these structural operations. 



ARC WELDING PROCEDURE 97 

The four factors which determine the physical character- 
istics of the metallic electrode arc welds are : Fusion, slag 
content, porosity and crystal structure. 

Some of the other important methods that have been sug- 
gested a-nd used for indicating these characteristics are : 

1. Examination of the weld by visual means to determine 
(a) finish of the surface as an index to workmanship; (b) 
length of deposits, which indicates the frequency of breaking 
arc, and therefore the ability to control the arc; (c) uniformity 
of the deposits, as an indication of the faithfulness with which 
the filler metal is placed in position; (d) fusion of deposited 
metal to bottom of weld scarf as shown by appearance of 
under side of welded joint; (e) predominance of surface 
porosity and slag. 

2. The edges of the deposited layers chipped with a cold 
chisel or calking tool to determine the relative adhesion of 
deposit. 

3. Penetration tests to indicate the linked unfusecl zones, 
slag pockets and porosity by (a) X-ray penetration; (b) rate 
of gas penetration; (c) rate of liquid penetration. 

4. Electrical tests (as a result of incomplete fusion, slag 
inclusions and porosity) showing variations in (a) electrical 
conductivity; (b) magnetic induction. 

These tests if used to the best advantage would involve their 
application to each layer of deposited metal as well as to the 
finished weld. This, except in unusual instances, would not 
be required by commercial practice in which a prescribed 
Welding process is carried out. 

Of the above methods the visual examination is of more 
importance than generally admitted. Together with it the 
chipping and calking tests arc particularly useful, the latter 
test serving to indicate gross neglect by the operator of the 
cardinal welding principles, due to the fact that only a very 
poor joint will respond to the tests. 

The most reliable indication of the soundness of the weld 
is offered by the penetration tests. Obviously the presence 
of unfused oxide surfaces, slag deposits and blowholes will 
offer a varying degree of penetration. Excellent results in 
the testing of small samples are made possible by the use of 
the X-ray. However, due to the nature of the apparatus, the 



98 ELECTRIC WELDING 

amount of time required and the difficulty of manipulating 
and interpreting results, it can hardly be considered at the 
present time as a successful means to be used on largc-scaio 
production. 

The rate that hydrogen or air leaks through a joint from 
pressure above atmospheric to atmospheric, or from atmospheric 
to partial vacuum, can readily be determined by equipment 
that would be quite cumbersome, and the slight advantage 
over liquid penetration in time reduction is not of sufficient 
importance to warrant consideration for most welds. 

Of the various liquids that may be applied kerosene has 
marked advantages because of its availability, low volatility 
and high surface tension. Due to the latter characteristics 
kerosene sprayed on a weld surface is rapidly drawn into any 
capillaries produced by incomplete fusion between deposited 
metal and weld scarf, or between succeeding deposits, slag 
inclusions, gas pockets, etc., penetrating through the weld and 
showing the existence of an unsatisfactory structure by a stain 
on the emerging side. A bright-red stain can be produced by 
dissolving suitable oil-soluble dyes in the kerosene. By this 
means the presence of faults have been found that could not 
be detected with hydraulic pressure or other methods. 

By the kerosene penetration a sequence of imperfect struc- 
ture linked through the weld, which presents the greatest 
hazard in welded joints, could be immediately located, but it 
should be borne in mind that this method is not applicable 
to the detection of isolated slag or gas pockets nor small, 
disconnected unfused areas. It has been shown by various tests, 
however, that a weld may contain a considerable amount of 
distributed small imperfections, without affecting to a great 
extent its characteristics. 

If a bad fault is betrayed by the kerosene test it is advis- 
able to burn out the metal with a carbon arc before rewelding 
under proper supervision. By the means of sandblast, steam 
or gasoline large quantities of kerosene are preferably removed. 
No difficulty has been encountered on welding over a thin 
film of the liquid. 

Electrical tests, by which the homogeneity of welds is 
determined, are still in the evolutionary stages, and many diffi- 
culties arc yet to be overcome before this test becomes feasible. 



ARC WELDING PROCEDURE 99 

Some of these difficulties are the elimination of the effect of 
contact differences, the influence of neighboring paths and 
fields, and the lack of practicable, portable instruments of suffi- 
cient sensibility for the detection of slight variations in con- 
ductivity or magnetic field intensity. No simple tests are 
plausible, excepting those which involve subjecting the metal 
to excessive stresses for determining the crystal structure. 
Control of this phase must be determined by the experience 
obtained from following a prescribed process. 

The inspector of metallic arc electrode welds may consider 
that through the proper use of visual, chipping and penetrating 
tests a more definite appraisal of the finished joint may be 
obtained than by either riveting or concrete construction. The 




FIG. 70. Typical Arc-weld Scarfs. 

operation may be still further safeguarded by requiring rigid 
adherence to a specified process. 

Good results are assured if correct procedure is followed. 

Haphazard welding can no sooner produce an acceptable 
product than hit-or-miss weaving will make a marketable cloth. 
It is only logical, that all the steps in a manufacturing opera- 
tion should be regulated to obtain the best results. As it is 
most welders consider themselves pioneers in an unknown art 
that requires the exercise of a peculiar temperament for its 
successful evolution, and as a result welding operators enshroud 
themselves in the halo of an expert and do their work with 
a mystery bewildering to the untutored. Once in a while, due 
we might say to coincidences, these "experts" obtain a good 
weld, but more often the good weld may he attributed to the 
friction between slightly fused, plastered deposits. 

In common with all other operations metallic electrode arfl 



100 ELECTRIC WELDING 

welding is really susceptible to analysis. Regardless of the 
metal welded with the arc the cardinal steps are: (1) Prepara- 
tion of weld; (2) electrode selection; (3) arc-current adjust- 
ment; (4) arc-length maintenance, and (5) heat treatment. 

Sufficient scarfing is involved in the preparation of the 
weld, as well as the separation of the weld slants, so that the 
entire surface is accessible to the operator with a minimum 
amount of filling required. When necessary to avoid distortion 
and internal stresses, owing to unequal expansion and contrac- 
tion strains, the metal is preheated or placed so as to permit 
the necessary movement to occur. Various types of scarfs in 
common use are shown in Fig. 70. 

The electrode selection is determined by the mass, thickness 





FIG. 71. Good and Bad Welds. 

and constitution of the material to be welded. An electrode 
free from impurities and containing about 17 per cent, carbon 
and 5 per cent, manganese has been found generally satis- 
factory for welding low and high carbon as well as alloy steels. 
This electrode can also be used for cast-iron and malleable-iron 
welding, although more dependable results, having a higher 
degree of consistency and permitting machining of welded 
sections, can be obtained by brazing, using a copper-aluminum- 
iron-alloy electrode and some simple flux. Successful results 
are obtained by brazing copper and brass with this electrode. 
The diameter of the electrode should be chosen with reference 
to the arc current used. 

A great many concerns have attempted welding with too 



ARC WELDING PROCEDURE 



101 



low an arc current and the result lias been a poorly fused 
deposit. This is due largely to the overheating characteristics 
of most electrode holders, or using current value, and thus 
leading the operator to conclude that the current used is in 
excess of the amount that is needed. 

A y Fig. 71, shows a section through one-half of an exposed 
joint welded with the proper current, and B the effects of too 
low a current. The homogeneity and the good fusion of the 
one may be contrasted with the porosity and poor fusion of 




GO 

Arc Current. 

FIG. 72 .Diameters for Welding Steal Plate. 



the latter. These surfaces have been etched to show the char- 
acter of the metal and the welded zone. 

The approximate values of arc current to be used for a 
given thickness of mild-steel plate, as well, as the electrode 
diameter for a given arc current, may be taken from the curve 
in Fig. 72. The variation in the strength of 1-in. square welded 
joints as the welding current is increased is shown in Fig. 73. 

Notwithstanding that the electrode development is still in 
its infancy the electrodes available are giving satisfactory 
results, but considerable strides can yet be made in the duc- 
tility of welds, consistency in results and ease of utilizing the 
process. 

The maintenance of a short arc length is imperative. A 
nonporous, compact, homogeneous, fused deposit on a 1-in. 



102 ELECTRIC WELDING 

square bar from a short arc is shown in Fig. 74, A, and in 5 
is shown a porous, diffused deposit from a long arc. Top 
views of these welds are shown in Fig. 75. A short arc is 



SO, 000 




o so ioo iso 

Amperes Jrc Current: 

p IG . 73. Variation in Weld Strength with Change in Arc Current. 



/* r r*f> j | 

( 

' I 



'/ wf & wwi 




J^Q 74. Sectional Views of Short and Long Arc Deposits. 

usually maintained by a skillful operator, as the work is thereby 
expedited, less electrode material wasted and a better weld 
obtained because of improved fusion, decreased slag content 



ARC WELDING PROCEDURE 103 

and porosity. On observing the are current and arc voltage 
by meter deflection or from the trace of recording instruments, 
the inspector has a continuous record of the most important 
factors which affect weld strength, ductility, fusion, porosity, 
etc. The use of a fixed series resistance and an automatic 
time-lag reset switch across the arc to definitely fix both the 
arc current and the arc voltage places these important factors 
entirely beyond the control, of the welder and under the direc- 
tion of the more competent supervisor. 

Heat Treatment and Inspection, The method of placing 
the deposited layers plays an important part on the internal 
strains and distortion obtained on contraction. It is possible 
that part of these strains could be relieved by preheating and 







FIG. 75. Top Views of Welds Shown in Fig. 74. 

annealing as well as by the allowance made in preparation 
for the movement of the metal. 

The heat treatment of a completed weld is not a necessity, 
particularly if it has been preheated for preparation and then 
subjected to partial annealing. A uniform annealing of the 
structure is desirable, even in the welding of the small sections 
of alloy and high-carbon, steels, if it is to be machined or 
subjected to heavy vibratory stresses. 

The inspector, in addition to applying the above tests to 
the completed joint and effectively supervising the process, 
can readily assure himself of the competency of any operator 
by the submission of sample welds to ductility and tensile 
tests or by simply observing the surface exposed on cutting 
through the fused zone, grinding its face and etching with a 
solution of 1 part concentrated nitric acid in 10 parts water. 

It is confidently assumed, in view of the many resources 
at the disposal of the welding inspector, that this method of 



104 ELECTRIC WELDING 

obtaining joints will rapidly attain successful recognition as 
a dependable operation to be used in structural engineering. 

EFFECTS OF THE CHEMICAL COMPOSITION OF METALLIC ARC 
WELDING ELECTRODES 

In order to ascertain to what extent the chemical analysis 
of an electrode affected the welded material in metallic arc 
welding, says J. S. Orton, two electrodes R and W were chosen 
of widely different chemical analyses, each 0.148 in. in diameter. 
The R electrode was within the specifications of the Welding 
Research Committee except that the silicon content was a little 
high. The analyses were as follows: 



jR wire 



0.17 


Mn 
0.57 


P 

0.007 


S 
0.028 


Si. 
14 


iy \virc 


0.39 


1.01 


0.005 


0.024 


12 















The silicon content was rather high, but inasmuch as it 
was fairly constant in both electrodes the results are com- 
parative. 

A deposit was made on a -J-in. plate by means of a metallic 
arc, the welded section being approximately 1 ft. long, 6 in. 
wide and 1 in. thick. The welding machine used was of a 
well-known make, with a constant voltage of 37 volts at 130 
amperes. The plates used for depositing the first layer were 
machined away and two test bars were made from each elec- 
trode, composed entirely of welded material. The ends were 
rough-machined and about 4|- in. in the middle of the specimens 
were finished carefully. 

The physical characteristics of the plates arc as shown in 
Table V. 

TABLE V. PHYSICAL CHARACTERISTICS OF PLATES 





Tensile 


Elastic 




KA 




Strength 


Limit 


Elongation 


Brinncl 


22-1 


57,300 


43,400 


8 


15 3 


o 


, 56,050 


50,500 


6 


5 9 


ir-i 


76,200 


64 000 


7 5 


13 


2 


72,650 


60 260 


5 5 


7 1 













After these bars were pulled, chemical analyses were taken 
at various points to get the values given in Table VI. 



ARC WELDING PROCEDURE 105 

TABLE VI. CHEMICAL ANALYSES OP SPECIMENS 



E-l 


C 
0.12 


Mn 
0.23 


P 
0.012 


s 

0.019 


Si 
0.10 


2 


0.09 


0.24 


0.016 


014 


0.08 


a 


11 


26 


014 


020 


08 


W-l 


0.23 


0.84 


0.014 


012 


02 


o 


0.20 


80 


014 


014 


05 


3 


20 


88 


013 


013 


02 















Photographs of the different fractures are shown in Fig. 
77. W-l, which gave the highest tensile strength, shows 100 
per cent, metallic structure with a silky appearance. R-l 
shows a coarse intergranular fracture. R-2 shows a brittle, 
shiny crystalline fracture with a slag inclusion at the lower 
left-hand and upper right-hand corners of the bars. W-2 




We 



FIG. 76. Fractures of Test Specimens. 

shows partial crystalline and partial silky fracture. At the 
extreme right there is a portion which is not welded. This 
is probably the reason why W-2 did not pull as much as the 
other. Undoubtedly, next to the chemical analysis, the quan- 
tity of slag in the weld has the biggest bearing on the tensile 
strength. 

The structure of the test specimens is shown in the micro- 
photographs of Fig. 77. In making these photographs, no 
attempt was made to make a complete microanalysis of the. 
two different specimens, but rather it was intended to show 
the general difference in structure between the two different 
types of electrode. All of these photographs were taken at 
150 diameters except the last two, which were taken at 100. 

Photograph R-l A shows the general structure of the plate 
welded with the R electrode. This photograph shows a large- 



106 



ELECTRIC WELDING 









ARC WELDING PROCEDURE 107 

grain growth and columnar structure which are characteristic 
of electric welds. Photograph Wl-A shows the general struc- 
ture of the plate welded with the W electrode. This shows 
comparatively small-grain structure. The structure seems to 
be much better than that of Rl-A. Photograph Rl-B shows 
a portion of a test specimen which was cut out of plate Rl 
and bent to an angle of 10 cleg. It is interesting to note here 
the opening up of the welded material adjacent to slag inclu- 
sions. Photograph Wl-B shows a portion of a small specimen 
cut out from sample Wl and bent to an angle of 10 dog., the 
same, as in the case of Rl-B. The welded material is opening 
up but not in the same degree nor around the slag inclusions 
as in the corresponding photograph Rl-B. Photograph Rl-C 
is a profile of the fracture of the Rl sample after bending 
through an angle of 15 dog. Photograph Wl-C shows the Wl 
sample after being bent through an angle of 17 degrees. 

It seems just as important to specify the chemical composi- 
tion of the electrode used in metallic are welding as it is to 
specify the chemical composition in ordering any other type 
of steel. 

Chemical composition seems to affect the physical properties 
in electrodes as well as other steel. 

An excess of manganese seems to be needed in electrodes. 

The relation between the carbon and manganese of an elec- 
trode should l)e approximately one to three. 

High-carbon manganese wire, tends not only to improve 
the weld on account of the amount of carbon and manganese 
in the welded material, but also on account of the type of 
structure which this wire lends to the deposited metal. 

There is a smaller amount of oxide and slag inclusions with 
a high-carbon manganese wire than with a comparatively low- 
carbon manganese wire. 

WELDING COMMITTEE ELECTRODES 

After an exhaustive series of tests the Welding Committee 
drew up the following tentative specification for electrodes 
intended to be used in welding mild steel of shipbuilding 

quality : 

Chemical Composition. Carbon, not over 0.18 per cent; 
manganese, not over 0.55 per cent; phosphorus, not over 0.05 



108 ELECTRIC WELDING 

per cent; sulphur, not over 0.05 per cent; silicon, not over 
0.08 per cent. 

Sizes : Fraction of Inch Lbs. Per Foot Toot Per Lb. Lbs. Per 100 Ft. 

1/8 0.0416 24 4.16 

5/32 0.0651 15.35 6.51 

3/16 0.0937 10.66 9.37 

Allowable tolerance 0.006 plus or minus. 

Material. The material from which the wire ivS manufac- 
tured shall be made by any approved process. Material made 
by puddling process not allowed. 

Physical Properties. Wire to be of uniform homogeneous 
structure, free from segregation, oxides, pipes, seams, etc., as 
proven by micro-photographs. This Avire may or may not be 
covered. 

Workmanship and Finish. (a) Electric welding- wire shall 
be of the quality and finish known as ''Bright Hard" or "Soft 
Finish." "Black Annealed" or "Bright Annealed" wire shall 
not be supplied, (&) The surface shall be free from oil or 
grease. 

Tests. The commercial weldability of these electrodes shall 
be determined by means of tests by an experienced operator, 
who shall demonstrate that the wire flows smoothly and evenly 
through the arc without any detrimental phenomena. 



CHAPTER VII 
ARC WELDING TERMS AND SYMBOLS 

In order to aid the standardization of the various types 
of joints and welding operations the practice recommended 
by the "Welding Committee of the Emergency Fleet Corp., for 




FIG. 78. Standard Symbols Kecommended by the Welding Committee of 
the Emergency Fleet Corporation. 



STRAP 




FIG. 79. 

ship work, is given. The symbol chart is shown in Fig. 78 
and the application of special terms and symbols is individually 
shown in Figs. 79 to 112 inclusive. 

109 



110 



ELECTRIC WELDING 



FIG. 79. A Strap weld is one in which the seam of two adjoin- 
ing plates or surfaces is reinforced by any form or shape to add 
strength and stability to the joint or plate. In this form of 
weld the seam can only be welded from the side of the work 
opposite the reinforcement, and the reinforcement, of whatever 

BUTT SYMBOL n 




PIC, 80. 

shape, must be welded from the side of the work to which 
the reinforcement is applied. 

FIG. 80. A Butt weld is one in which two plates or surfaces 
are brought together edge to edge and welded along the scam 
thus formed. The two plates when so welded form a perfectly 



LAP 




FIG. 81. 

flat plane in themselves, excluding the possible projection 
caused by other individual objects as frames, straps, stiffcners, 
etc., or the building up of the weld proper. 

FIG. 81. A Lap weld is one in which the edges of two 
planes are set one above the other and the welding material so 
applied as to bind the edge of one plate to the face of the 



ARC WELDING TERMS AND SYMBOLS 



111 



other plate. In this form of weld the seam or lap forms a 
raised surface along its entire extent. 

FIG. 82. A Fillet weld is one in which some fixture or 
member is welded to the face of the plate, by welding along 



FILLET 




"A" 



FIG. 82. 



the vertical edge of the fixture or member (see welds shown 
and marked A). The welding material is applied in the corner 
thus formed and finished at an. angle of forty-five degrees to 
the plate. 

FIG. 83. A Plug weld is one used to connect the metals by 



PLUG 




FIG. S3, 



welding through a hole in either one plate A or both plates B. 
Also used for filling through a bolt hole as at C, or for added 
strength when fastening fixtures to the face of a plate by 
drilling a countersunk hole through the fixtures and applying 
the welding material through this hole, as at D, thereby fasten- 
ing the fixture to the plate at this point. 



112 



ELECTRIC WELDING 



FIG. 84. A Tee weld is one where one plate is welded 
vertically to another as in the ease of the edge of a transverse 
bulkhead A, being welded against the shellplating or deck. 
This is a weld which in all cases requires exceptional care and 
can only be used where it is possible to work from both sides 




of the vertical plate. Also used for welding a rod in a vertical 
position to a flat surface, as the rung of a ladder C, .or a plate 
welded vertically to a pipe stanchion B, as in the case of water 
closet stalls. 

FIG. 85. A Single "V" is applied to the "edge finish" 
of a plate when this edge is beveled from botli sides to an 



SINGLE "V" 




FIG. 85. 



angle, the degrees of which are left to the designer. To be 
used when the "V" side of the plate is to be a maximum 
"strength" weld, with the plate setting vertically to the face 
of adjoining member, and only when the electrode can be 
applied from both sides of the work. 



ARC WELDING TERMS AND SYMBOLS 



113 



FIG. 86. Double "V" is applied to the "edge finish" of 
two adjoining plates when the adjoining edges of both plates 



DOUBLE "V" 




PIG. 86. 



1 THICKNE! 



beveled from both sides to an angle, the degrees of which are 
left to the designer. To be used when the two plates are to 
be "butted" together along these two sides for a maximum 



STRAIGHT 



SYMBOL 

I 



1C NOTES BELOW 




FIG. 87. 



"strength" weld. Only to be used when welding can be per- 
formed from both sides of the plate. 

FIG. 87. Straight is applied to the "edge finish" of a plate, 
when this edge is left in its crude or sheared state. To be 



SINGLE BEVEL 



< 




PIG. 88. 

used only where maximum strength is not essential, or unless 
used in connection with strap, stiffener or frame, or where 
it is impossible to otherwise finish the edge. Also to be used 



114 



ELECTRIC WELDING 



for a "strength" weld, when edges of two plates set vertically 
to each other as the edge of a box. 

FIG. 88. Single Bevel is applied to the edge finish of a 



DOUBLE BEVEL 




FIG. 89. 



plate, when this edge is beveled from one side only to an angle, 
the degrees of which are left to the designer. To be used 
for "strength" welding, when the electrode can be applied 



DECK PLATING 




FIG. 90, 

from one side of the plate only, or where it is impossible to 
finish the adjoining surface. 

PIG. 89. Double Bevel is applied to the edge finish of two 
adjoining plates, when the adjoining edges of both plates are 



ARC WELDING TERMS AND SYMBOLS 115 

beveled from one side only to an angle, the degrees of which 
are left to the designer. To be used where maximum strength 
is required, and where electrode can be applied from one side 
of the work only. 

FIG. 90. Flat position is determined when the welding- 
material is applied to a surface on the same plane as the deck, 
allowing the electrode to be held in an upright or vertical 
position. The welding surface may be entirely on a plane 
with the deck, or one side may be vertical to the deck and 
welded to an adjoining member that is on a plane with the 
deck. 

Horizontal position is determined when the welding material 
is applied to a seam or opening, the plane of which is vertical 
to the deck and the line of weld is parallel with the deck, 




FIG. 91. 

allowing the electrode to be held in an inboard or outboard 
position. 

Vertical position is determined when the welding material 
is applied to a surface or seam, whose line extends in a direc- 
tion from one deck to the deck above, regardless of whether 
the adjoining members are on a single plane or at an angle 
to each other. In this position of weld, the electrode would 
also be held in a partially horizontal position to the work. 

Overhead position is determined when the welding material 
is applied from the under side of any member whose plane 
is parallel to the deck and necessitates the electrode being 
held in a downright or inverted position. 

jn IG> 91. A Tack weld is applying the welding in small 
sections to hold two edges together, and should always be 
specified by giving the space from center to center to weld 
and the length of the weld itself. No particular "design of 
weld" is necessary of consideration. 



116 



ELECTRIC WELDING 



A Tack is also used for temporarily holding material in 
place that is to be solidly welded, until the proper alinement 
and position is obtained, and in this case neither the lengtli, 
space, nor design of weld are to be, specified. 

FIG. 92. A Caulking weld is one in which the density of 



CAULKING 




FIG. 92. 



the crystalline metal, used to close up the seam or opening, 
is such that no possible leakage is visible under a water, oil 
or air pressure of 25 Ibs. per square inch. The ultimate strength 
of a caulking weld is not of material importance neither is 
the "design of weld" of this kind necessary of consideration. 
FIG. 93. A Strength weld is one in which the sectional 



STRENGTH 




. 93. 



area of the welding material must be so considered that its 
tensile strength and elongation per square inch must equal 
at least 80 per -cent of the ultimate strength per square inch 
of the surrounding material. (To be determined and specified 
by the designer.) The welding material can be applied in 
any number of layers beyond a minimum specified by the 
designer. 

The density of the crystalline metals is not of vital im- 



ARC WELDING TERMS AND SYMBOLS 



117 



portance. In this form of weld, the "design of weld" must 
be specified by the designer and followed by the operator. 

FIG. 94. A Composite weld is one in which both the strength 
and density are of the most vital importance. The strength 
mnst be at least as specified for a "strength wold," and the 
density must meet the requirements of a "caulking weld" 



COMPOSITE 




FIG. 94. 

both as above defined. The minimum number of layers of 
welding material must always be specified by the designer, 
but the welder must be in a position to know if this number 
must be increased according to the welder's working con- 
ditions. 

FIG. 95. Reinforced is a term applied to a weld when the 
top layer of the welding material is built up above the plane 



REINFORCED 



^ DOTTED LINES SHOW T 



I FLUSH SOKJACt N 




FIG. 95. 

of the surrounding material as at A or B, or when used for 
a corner as at C. The top of final layer should project above 
a plane of 45 degrees to the adjoining material. This 45 degree 
line is shown "dotted" in 0. This type is chiefly used in a 
"strength" or "composite" kind of weld for the purpose of 
obtaining the maximum strength efficiency, and should be speci- 
fied by the designer, together with a minimum of layers of 
welding material. 



118 



ELECTRIC WELDING 



FIG. 96. Flush is a term applied to a weld when the top 
layer is finished perfectly flat or on the same plane as on the 
adjoining material as shown at D and E or at an angle of 
45 degrees when used to connect two surfaces at an angle to 
each other as at F. This type of weld is to be used where a 
maximum tensile strength is not all important and must bo 



RUSH 




FIG. 90. 

specified by the designer, together with a minimum number 
of layers of welding material. 

FIG. 97. Concave is a term applied to a weld when the 
top layer finishes below the plane of the surrounding material 
as at G-, or beneath a plane of 45 degrees at an angular con- 
nection as at H and J. 

To be used as a weld of no further importance than filling 




FIG. 97. 

ill a seam or opening, or for strictly caulking purposes, when 
it is found that a minimum amount of welding material will 
suffice to sustain a specified pound square inch pressure with- 
out leakage. In this "type of weld" it will not be necessary 
for the designer ordinarily to specify the number of layers 
of material owing to the lack of structural importance. 

COMBINATION SYMBOLS 

FIG. 98 shows a strap holding two plates together, setting 
vertically, with the welding material applied in not less than 
three layers at each edge of the strap, as well as between 
the plates with a reinforced, composite finish., so as to make 
the welded seams absolutely water, air or oil tight, and to 



ARC WELDING TERMS AND SYMBOLS 



119 



attain the maximum tensile strength. The edges of the strap 
and the plates are left in a natural or sheared finish. This type 
of welding is used for particular work where maximum strains 
are to be sustained. 

FIG. 99 shows a strap holding two plates together liori- 



STRAP WELD, REINFORCED, 
COMPOSITE OF THREE LAYERS, 
VERTICAL, STRAIGHT, 




/ ^ 






S& 










VERTICAL WELD 


I 




PLATE 




STRAP 


I 


PLATE 




I 






/ 



PIG. 98. 

zontally, welded as a strength member with, a minimum of 
three layers and a flush finish. Inasmuch as the strap neces- 
sitates welding of the plates from one side only, both edges 
of the plates are bevelled to an angle, the degrees of which 
are left to the discretion of the designer. The edges of the 



STRAP WELD, FLUSH, 
STRENGTH OF 3 LAYERS, 
HORIZONTAL, FLAT AND 
OVERHEAD, DOUBLE BEVEL 




HORIZONTAL WELD* 



OVERHEAD WELD 




G. 99. 



strap are left in a natural or sheared state, and the maximum 
strength, is attained by the mode of applying the welding 
material, and through the sectional area per square inch exceed- 
ing the sectional area of the surrounding material. 

FIG. 100 represents two plates butted together and welded 



120 



ELECTRIC WELDING 



Hat, with a composite weld of not less than three layers, and 
a reinforced finish. A strap is attached by means of overhead 
tacking, the tacks being four inches long and spaced eight 
inches from center to center. In this case, the welding of 
the plates of maximum strength and water, air or oil tight, 



6-O8-4\ ST 
9 3 F 8" 

ZJ 4- 



STRAP, TACK, OVERHEAD. 
CENTER TO CENTER 
LONG, BUTT, REINFORCED 

COMPOSITE OF 3 LAYERS, 

FLAT. STRAIGHT. 



FLAT WELD 




OVERHEAD \VELD - 



FIG. 100. 

but the tacking is either for the purpose of holding the strap 
in place xuitil it may be continuously welded, or because 
strength is not essential. All the edges are left in their natural 
or sheared state. 

FIG. 101 represents a butt weld between two plates with 
the welding material finished concaved and applied in a mini- 



WELD. CONCAVE. 
CAULKING OF 2 LAYERS. 
FLAT. STRAIGHT 




FIG. 101. 

mum of two layers to take the place of caulking. The edges 
of the plates are left in a natural shear cut finish. This symbol 
will be quite frequently used for deck plating or any other- 
place where strength is not essential, but where the material 
must be water, air or oil tight. 

FIG. 102 is used where the edges of two plates are vertically 



ARC WELDING TERMS AND SYMBOLS 



121 



butted together and welded as a strength member. The edges 
of adjoining plates are finished with a "double vee" and the 
minimum of three layers of welding material applied from 
each side, finished with a convex surface, thereby making the 
sectional area per square inch of the weld greater than that 



,83V 

X 



BUTT WELD, REINFORCED. 
STRENGTH OF 3 LAYERS, 
VERTICAL, DOUBLE VEE. 



DOUBLE VEE 




PIG. 102. 

of the plates. This is a conventional symbol for shell plating 
or any other members requiring a maximum tensile strength, 
where the welding can be done from both sides of the work. 
FIG. 103 shows two plates butted together in a flat position 
where the welding can. only be applied from the top surface. 
It shows a weld required for plating where both strength and 



BUTT WELD, FLUSH, 
COMPOSITE OF 3 LAYERS. 
FLAT. DOUBLE BEVEL. 




DOUBLE BEVKI. 

Fis. 103. 

watertightness are to be considered. The welding material 
is applied in a minimum of three layers and finished flush with 
the level of the plates. Both edges of the adjoining plates 
are beveled to an angle, the degrees of which are left to the 
discretion and judgment of the designer, and should only be 
used when it is impossible to weld from both sides of the work. 



122 



ELECTRIC WELDING 



. 104 shows the edges of two plates lapping each other 
with the welding material applied in not less than two layers 
at each edge, with a concaved caulking finish, so applied, as 
to make the welded seams absolutely water, air or oil tight. 



LAP WELD, CONCAVE, 
CAULKING OF 2 LAYERS, 
OVERHEAD AND FLAT 
STRAIGHT 




OVERHEAD WELD 



FIG, 104. 



The edges of the plates themselves are left in. a natural or 
shared finish. Conditions of this kind will often occur around 
bulkhead door frames where maximum, strength, is not ab- 
solutely essential. 

FIG. 105 is somewhat exaggerated as regards the bending 



LAP WELD. REINFORCED, 
STRENGTH OF 3 LAYERS 
AND TACKING, 18" CENTER 
TO CENTER, 6' LONG. 
VERTICAL, STRAIGHT. 




Fro. 105. 

of the plates, but it is only shown this way to fully illustrate 
the tack and continuous weld. It shows the edges of the 
plates lapped with one edge welded with a continuous weld 
of a minimum of three layers with a reinforced finish thereby 
giving a maximum tensile strength to the weld, and the other 



ARC WELDING TERMS AND SYMBOLS 



123 



edge of the plate, tack welded. The tacks arc six inches long 
with a space of 12 inches between the welds or 18 inches from 
center to center of welds. In both cases, the edges of the 
plates are left in a natural or sheared state. 



PLUG AND LAP WELD. 
STRENGTH OF 3 LAYERS 
FLUSH. FLAT. OVERHEAD, 
HORIZONTAL. 




FIG. 106. 

FIG. 106 shows a condition exaggerated, which is apt to 
occur in side plating where the plates were held in position 
with bolts for the purpose of alinement before being welded. 
The edges are to be wedded with a minimum of three layers 
of welding material for a strength weld and finished flush, 



PLUG AND FILLET WELD, 
REINFORCED, STRENGTH OF 
3 LAYERS, FLAT, SINGLE 
BEVEL AND STRAIGHT. 




FIG. 107. 

and after the bolts are removed, the holes thus left are to be 
filled in with welding material in a manner prescribed for 
strength welding. The edges of the plates are to be left in 
a natural or sheared state, which is customary in most cases 
of lapped welding. 



124 



ELECTRIC WELDING 



FIG. 107 shows a pad eye attached to a plate by means 
of a fillet weld along the edge of the fixture, and further 
strengthened by plug welds in two countersunk holes drilled 
in the fixture. The welding material is applied in a flat 
position for a strength weld with a minimum of three layers 

FILLET WELD, REINFORCED. 
COMPOSITE OF 3 LAYERS, 
FLAT, VERTICAL AND 
OVERHEAD. STRAIGHT. 




FIG. 108. 

and a reinforced finish. The edges of the holes are beveled 
to an angle, which is left to the judgment of the designer, 
but the edges of the fixture are left in their natural state. 
This method is used in fastening fixtures, clips or accessories 
that would be subjected to an excessive strain or vibration 



FILLET WELD, FLUSH, 
STRENGTH OF 3 LAYERS 
FLAT. STRAIGHT. 




FlG. 109. 



PIG. 108 shows a fixture attached to a plate by means of 
a composite weld of not less than three layers with a reinforced 
finish. The fixture being placed vertically, necessitates a com- 
bination of flat, vertical and overhead welding in the course 
of its erection. Although a fixture of this kind would never 



ARC WELDING TERMS AND SYMBOLS 



125 



be required to be watertight, the composite symbol is given 
simply as a possibility of a combination. 

FIG. 109 represents a fixture attached to a plate by a 
strength fillet weld of not less than three layers, finished flush. 



TEE WELD. FLUSH. 
STRENGTH OF 3 LAYERS. 
FLAT. SINGLE VEE. 




PIG. 110. 

The edges of the fixture are left in their natural state, and 
the welding material applied in the corner formed by the 
vertical edge of the fixture in contact with the face of the plate. 
FIG. 110 illustrates the edge of a plate welded to the face 
of another plate, as in the case of the bottom of a transverse 



TEE WELD, REINFORCED. 
STRENGTH OF 3 LAYERS. 
VERTICAL, SINGLE VEE. 




PIG. 111. 



bulkhead being welded against the deck plating. To obtain 
a maximum tensile strength at the joint, the edge of the plate 
is cut to "single vee" and welded on both sides with a strength 
weld of not less than three layers, and finished flush. This 
would be a convenient way of fastening the intercostals to 



126 



ELECTRIC WELDING 



the keelsons. In this particular case, the welding is done in 
a flat position. 

FIG. Ill shows another case of tee weld with the seam set- 
ting in a vertical position, and the welding material applied 
from both sides of the work. The edge of the plate is finished 
with a " single vee" and a minimum of three layers of welding 
material applied from each side, finished with a convex surface, 
thereby making the sectional area, per square inch of the weld, 
greater than that of the plate, allowing for a maximum tensile 
strength in the weld. 

FIG. 112 represents an example of the possible combination 



STRAP AND TEE WELD, 
FLAT, REINFORCED, TACK, 
12" CENTER TO CENTER, 
6" LONG, SINGLE BEVEL, 
OVERHEAD. STRENGTH OF 
3 LAYERS, FLUSH 





FIG. 112. 

of symbols. An angle iron is tack welded to the plate in the 
form of a strap or stiffener, though in actual practice, this 
might never occur. The tacks are spaced twelve inches from 
center to center, and are six inches long, and applied in a 
flat position, with a reinforced finish. As the strap prevents 
welding the plate from both sides, the edge of the plate is 
beveled, and the welding material applied for strength in not 
less than three layers in an overhead position and finished 
flush. Note that in specifying tack welds, it is essential to 
give the space from center to center of weld, and length of 
weld by use of figures representing inches placed either side 
of the circumscribing symbol of the combination. 



CHAPTER VIII 
EXAMPLES OF ARC-WELDING JOBS 

Probably no mechanical job ever attracted more general 
attention than the repair of the German ships seized by us 
when we entered the World War. Even the mechanically 
minded Germans repeatedly declared that repairing was an 
impossibility, but the American engineers and mechanics 
si 10 wed the Hun that he had, as usual, vastly over-rated his 
own knowledge. One big factor in making the. Hun. so positive 
in this case, was his utter ignorance regarding the possibilities 
of arc welding but lie learned and in the teaching many 
others were also enlightened. 

The. work necessary on these Herman, ships, of course, in- 
cluded much besides welding of the broken castings, but the 
welding work was of primary importance. 

The principal ships on which this welding work was done 
were the : 









Gross 


Class of 


U.S. Name 


German name 


T.H.P. 


Tonnage 


Vessel 


Aeolus 


G rosser Kurf nrst 


8,400 


13,102 


Transport 


Agamemnon 


Kaiser Wilholm IF. . . . 


45,000 


19,361 


Transport 


America 


America 


.1.5,800 


22,621 


Transport 


Antigno 


Nockar 


5,500 


9,835 


Transport 


Oovington 


Cincinnati 


10,900 


16,339 


Transport 


George Washington. 


George Washington... . 


21,000 


25,570 


Transport 


Huron 


Friedrie.h der G rosso. . 


6,800 


10,771 


Transport 


Leviathan 


Vaterland 


90,000 


54,282 


Transport 


Madawaska 


Koenig Wilholm FT.... 


, 7,400 


9,410 


Transport 


Martha Washington 


Martha Washington. . . 


6,940 


8,3.12 


Transport 


Mercury 


Barbarossa 


7,200 


10,984 


Transport- 


Mt. Vernon 


Kronprinzessin Oeeelie. 


45,000 


19,503 


Transport 


Pocahontas 


Prinzess Irene 


9,000 


10,983 


Transport 


Powhatan 


Hamburg 


9,000 


10,893 


Transport 


President Grant. . . 


President Grant 


8,500 


18,072 


Transport 


P r es i cl en t L i n c ol n . . 


President Lincoln 


8,500 


18,168 


Transport 


Savannah 


Saxonia 


2,500 


4.424 


Repair Shop 


Susquehanna 


lihcin 


9,520 


10.058 


Transport 


Philippines 


Bulgaria 


4,200 


10,924 


Shipping Bd. 



127 



128 ELECTRIC WELDING 

The total gross tonnage of the ships named was 288,780 
tons, and the welding work was done by the Wilson "Welder 
and Metals Co. of New York, using their "plastic-arc" process. 

Seventy Cylinders Saved Without Replacement. In all, 
there were thirty-one ships interned in the port of New York. 
Of those thirty-one ships, twenty-seven were German and four 
Austrian. Of the German ships, two were sailing vessels and 
four were small steamers which the Germans had not taken 
pains to damage materially. This left twenty-one German 
ships whose engines and auxiliaries were damaged seriously, 
ranging in size from the "Vaterland," the pride of the Ham- 
burg-American Line, of 54,000 tons, to the "Nassovia," of 
3,900 tons. 

On the cylinders of the twenty vessels of German origin, 
not counting for the moment the turbine-driven "Vaterland," 
there were no less than 118 major breaks which would have 
entailed the renewal of some seventy cylinders if ordinary 
practice had been followed. In fact, such was the recommenda- 
tion of the surveying engineers in their original report. 

To any engineer familiar with the conditions at that time 
in the machine shops and foundries in the vicinity of New 
York, also in the drafting rooms, the problem of producing 
seventy cylinders of the sizes required by these vessels would 
seem almost impossible, and it is pretty well established that 
some vessels would have had to wait nearly two years for 
this equipment. 

It must be remembered that few drawings of these engines 
were available, and those in many cases were not discovered 
until months after the repairs had started. Therefore, it would 
have been necessary to make drawings from the actual 
cylinders, and competent marine engine draftsman not already 
flooded with work did not exist. 

The cylinders of fifteen vessels were successfully welded, 
while those of six were repaired by fitting mechanical patches, 
or, in other words, eighty-two of the major breaks were repaired 
by welding and thirty-six by mechanical patches. 

It was not until July 12 that the final decision was made 
placing the transport service in the hands of the Navy and 
designating what ships were to be transferred from the control 
of the Shipping Board to that of the Navy Department. How- 



EXAMPLES OF ARC-WELDING JOBS 129 

ever, the first two large ships, the "Friedrich der Grosse/ 7 
now the "Huron," and the "Prinzess Irene/' now the "Poca- 
hontas," were ready for sea on Aug. 20, in spite of the fact 
that the engines on these vessels were among the worst damaged 
of them all, the "Irene" having ; :.tfe;;^Ql.e- side of the first 
intermediate valve chest broken out on each engine, the side 
of the high-pressure cylinder on each engine destroyed, and 
other smaller breaks, which, under ordinary methods, would 
have necessitated the renewal of four cylinders. The "Fried- 
rich der Grosse ' ' had the following breaks : Broken valve chest 
of high-pressure cylinder of each engine (valve chest cast in 
one with the cylinder), flanges knocked off both valve chest 
and cylinder covers, steam inlet nozzles knocked off both first 
intermediate valve chests and walls between the two valves 
in each check broken out, also steam inlet nozzles on both 
second intermediate valve chests broken off. 

. These two vessels were the first in which straight electric 
welding was used, that is, where patches were not bolted to 
the cylinder walls. 

Method of Repair. The nature of some of the breaks in 
castings is shown by the accompanying photographs, which 
were taken at various stages of the work. 

A, Fig. 113, shows the break in the starboard high-pressure 
cylinder of the North German Lloyd steamer "George Wash- 
ington. ' ' This break was effected by drilling a row of holes about 
an inch apart and knocking the piece out with a ram. 

To prepare this for welding it was necessary to chisel off 
the surface only roughly, build a pattern of the break, cast 
a steel piece from the pattern, stud up the surface of the cast 
iron of the cylinder with a staggered row of steel studs f in. in 
diameter, projecting \ in. from the cylinder, bevel the edge of 
the east piece, place the piece in position as shown in B, and 
make the weld. When completed, the appearance of the work 
is as it appears in C. The broad belt of welded metal is due 
to the laying of a pad of metal over the rows of studs previously 
noted. 

It cannot be too strongly insisted that tests have shown con- 
clusively that the weld can be properly made without this pad; 
that is, if the approximate strength of the original metal is all 
that is desired in which case the studding of the metal is 



130 



ELECTRIC WELDING 




bo 

fl 



CO 



a 

w 



0- 

-p 

pq 



EXAMPLES OF ARC- WELDING JOBS 131 

unnecessary. But the work in these particular cases was of 
vital importance, due to the uses to which the vessels were 
to be put when in service, and also it was appreciated that this 
exhibition of a new application of the art in the marine engineer- 
ing world required that the demonstration be satisfying, not only 
to the mind of the engineer, but to the eye, and ear, and when 
any engineer looked at that band of metal and sounded it with 
a hammer, he could not be but satisfied that the strength was 
definitely there and that the method of padding could be used 
in most of the situations which would arise. This at least was 
the effect upon all the engineers who saw the actual work. 

The metal was laid on in layers in such a manner as to 
take care of the contraction in cooling. Each successive layer 
was cleaned with a wire brush before the next layer was put 
on. It is in the keeping of the successive layers clean and 
in the laying on of the metal so as to take care of the con- 
traction that the operator's ability comes in fully as much 
as it does in the handling of the apparatus. The cylinders 
were not removed, but were repaired in place. Thus the work 
of fitting was reduced to a negligible quantity, and the refitting 
of lagging was not interfered with by projections, other than 
the -g-in. pad, which is laid over the studs for extra strength. 
It will also be noted that these repairs can be undertaken at 
any place where the vessel may be lying, either at her loading 
dock or in the stream, since such apparatus may be carried 
on barges, which can be placed alongside and wires run to 
the work. 

In this work a part consisted of the caulking of the surface 
of the welds which prevents porosity and also locates any 
brittle spots or places where poor fusion of metal has been 
obtained. This permits the cutting out of the bad places and 
replacing with good metal. The tool used was an air caulking 
hammer operated at 110 Ib. air pressure. 

Strength of Cast-iron Welds. Capt. E. P. Jessop, U. S. N., 
personally tested many welds for tensile strength in which 
cast iron was welded to cast steel, and in but one case was 
there a failure to obtain practically the original strength. This 
case was due, to an inexperienced operator burning the metal, 
and was easily detected as an inferior weld without the strength 
test being applied. 



132 ELECTRIC WELDING 

Much has been said about the effect of the heat of welding, 
upon the structure or strength of cast iron, and in this 
particular instance the Navy engineer who had direct charge 
of this work, made experiments to note if there, were any 
deleterious effects on the iron resulting 1 from the action of 
the weld and reported as follows: 

' ' iScleroseopic investigation of the structure of the welds shows only 
a very slight vein of hard cast iron at the line of the weld, shot through 
with fingers of gray east iron, while behind this area there was no heat 
effect whatever. The metal thus deposited wan easily workable with ham- 
mer and chisel, file or cutting tool. Another very important feature is 
that with the use of the low voltage and absolute automatic current control 
of tho Wilson system, there is a minimum of heat transmitted to the parts 
to bo welded, this being practically limited to a heat value absolutely 
necessary to bring the electrode and the face of the metal to be welded 
into a semi-plastic state, thus insuring a perfect physical union, and in 
accomplishing this result neither of the metals suffers from excessive heat, 
and there is absolutely no necessity for p re-heat ing. Neither are there 
any adverse results from shrinkage following the completed work owing 
to a minimum amount of heat being transmitted to the repair parts, thus 
avoiding the possibility of distortion of parts through uneven or excessive 
shrinkage strains that are very common whore pre-hoating is necessary or 
excessive heat is used for fusing metals. " 

A, Fig. 114, shows the damage done to the first intermediate 
cylinder of the U. S. S. " Poeahontas, ' ' formerly the "Prinzess 
Irene. 7 ' The damage to this cylinder, it will be noted, was more 
destructive than to that of the "George Washington/' rendering 
the repairs much more difficult. 

B shows the steel section in place ready for welding, with 
the surfaces properly VM out and with, a staggering row oil 
steel studs adjacent to the welding edge of the cylinder section. 

C shows the complete job with the extra band or pad of 
metal completely covering the studs on the cast-iron section. 
These bands or pads of metal are peaned or worked over with 
a pneumatic hammer to insure protection against porosity of 
metal. 

Had either or both of these cylinders been fractured on the 
lines shown of the cast-iron sections, and none of the parts 
removed, then the surfaces or edges of all lines of fracture 
would have been VM out, and the weld made of the two cast- 
iron surfaces in the same manner that the cast steel was welded 
to the cast-iron cylinder proper. 



KXAMPLKS OF AUC-WKLDINCl JOBS 



133 




134 ELECTRIC WELDING 

OTHER SHIP WORK 

In line with the foregoing J. 0. Smith, writing in the 
American Machinist, Jan. 22, 1920, says: When the matter of 
welding in connection with ship-construction is considered, im- 
mense possibilities immediately suggest themselves. It has 
been definitely determined by exhaustive technical study and 
experiment that welding can be satisfactorily employed in 
ship construction, that ship plates joined by welding will be as 
strong or stronger than the original metal at the welded joint, 
and that welding can be employed for ship-construction work 
at a saving of 25 per cent, in time and 10 per cent, in material, 
as compared to riveting. 

In actual figures, as determined by experiments of the 
Emergency Fleet Corporation's electric welding committee, it 
was determined that, by welding, in the case of a 9500-ton 
ship the saving in rivets and overlapped plates would amount 
in weight to 500 tons, making it possible for the ship to carry 
500 tons more cargo on each trip than would be possible if 
the ship plates, etc., had been riveted, instead of welded. 

An investigation "by the same committee has definitely 
established the following points : That electric-welded ships 
can be built at least as strong as riveted ships ; that plans for 
ships designed to be riveted can easily be modified so as to 
adapt them for extensive electric welding, and thus save con- 
siderably in cost and time for hull construction ; that ships 
especially designed for electric welding can be built at a saving 
of 25 per cent, over present methods and in less time. 

An electrically welded ship is credited with many ad- 
vantages over a riveted ship. In a 5000-ton ship, about 450,000 
rivets arc used. A 9500-deadweight-ton ship requires 600,000 
or 700,000 rivets. By the welding process the saving in labor 
on the minor parts of a ship is reckoned at from 60 to 70 
per cent, on the hull, plating and other vital parts ; the saving 
in labor, cost and time of construction by welding is conserva- 
tively placed at 25 per cent. 

That electric welding will some day largely replace riveting 
is also the judgment of the electric-welding committee which 
is composed of many leading experts in both the electrical 
and metallurgical branches of the welding field. 



EXAMPLES OF ARC-WELDING JOBS 135 

Considerable investigation of the subject of welding instead 
f riveting has been made in England by Lloyd's Kegister of 
hipping, particularly with regard to formulating rules for 
pplication to the electrical welding of ships. As a result of 
ic investigations and experiments made by the technical staff, 
was determined that the matter had assumed such importance 
3 to warrant the formulation of provisional rules for elec- 
ically welded vessels, and these have been issued, for the 
uidance of shipbuilders, by Lloyd's Register. 

The experiments conducted in England followed three well- 
efined lines of investigation : Determination of ultimate 
;,rength of welded joints, together with their ductile proper- 
.es; capability of welded joints to withstand alternating ton- 
ic and compressivc stresses, such as are regularly experienced 
y ships; and a microscopic and metallurgical analysis to 
etermine if a sound fusion was effected between the original 
ad added metal. 

It was determined that the tensile strength of the welded 
)ints was from 90 to 95 per cent, of the original plates, as 
gainst a strength of from 65 to 70 per cent, in riveted joints, 
lowing a margin of 25 per cent, increased strength in favor 
the welded joints. 

The result of the tests of the elastic properties of welded 
)ints determined that there was a slight difference in favor 
f the riveted joint, but the art of welding has made such great 
rides recently that it is now believed entirely possible to 
take a welded joint in ship plates that will stand as great a 
umber of reversals of stresses as a riveted joint. 

Microscopic and metallurgical analyses have determined 
lat a good, solid, mechanically sound weld was made between 
ic original and the added metal, the two having been fused 
)gethcr so perfectly that no line of demarcation could be seen. 

The rules so far promulgated by Lloyd's (January, 1920), 
ave been necessarily of a tentative nature and will no doubt 
e modified and enlarged from time to time in view of the 
xpcriencc that will be gained after welded ships have been 
i service for a time. 

It does not require a great deal of imagination, however, 
D enable anyone to form the opinion that the shipbuilding 
idustry is on the eve of great modifications in constructional 



136 ELECTRIC WELDING 

lines, and the guidance given by the tests and comparisons 
so far made will undoubtedly lead to important, radical de- 
partures and developments. 

In addition to the increased cost of riveting as compared 
to welding, it is practically always true that there is a certain 
percentage of imperfectly fitted rivets, that do nothing more 
than add weight to the ship. The main purpose of a rivet, 
of course, is to bind two or more thicknesses of material to- 
gether, but if the rivet is bent, loses part of its head in the 
riveting process or otherwise fails in its proper purpose, there 
is no method by which such faults can be corrected after the 
rivet cools. If the importance of the riveted part requires 
a perfect joint, the faulty rivets must be removed entirely, 
and this is frequently a time-killing, expensive course to fol- 
low. When it is considered that a 5500-ton ship requires 
approximately 450,000 rivets to bind the various parts and 
plates and also that a certain percentage of these rivets is 
not fulfilling the purpose for which they were put into the 
ship, it is quite evident that practically every ship is burdened 
with a good-sized load of dead, useless weight. Such defective 
rivets are, in fact, more than a useless weight, in that they 
are a menace to the ship, for while they have been built into 
the ship for a purpose, and are supposed to be fulfilling that 
purpose, there is no telling how much the ship has been weak- 
ened structurally by their failure. 

There are many reasons for defective rivets, and one of 
the greatest of them is the inaccessibility of the parts to be 
riveted and the consequent difficulty on the part of the riveter 
in putting the rivets properly in place. Another reason is that 
there is no certainty that rivets are at a proper, workable 
temperature; in consequence of which if they are too cold, 
the pneumatic hammer now generally used in riveting is unable 
to round off the end of the rivet properly, so as to insure a 
proper binding together of the plates the rivet is supposed 
to hold. 

In many cases, when such faulty rivets are discovered, the 
present-day method is to weld such defective spots, which 
immediately brings up the natural question as to why the 
plates should not be welded in the first place. 

The ability of a welder, using a direct-current, low-voltage 



EXAMPLES OF ARC-WELDING JOBS 



137 



are with automatically regulated current to make sound 
mechanical welds in cramped, confined spaces, on overhead 




TIG. 115. Welded Parts for Ships. 



or vertical walls, in fact, anywhere a man and a wire can go, 
naturally suggests that welding ship plates together should be 
the primary operation in shipbuilding; and from present in- 




FIG. 116. Welded Fuel-Oil Tanks. 

dications and the trend of current events, it seems more than 
likely that this will be the outcome in the near future, 

Examples of various ship parts welded by the metallic arc 



138 KLECTKIC WELDING 

are shown in Fig. 115. In Pig. H6 is shown a welded tank 
and in Fig. 117 a welded steel-plate, 4X7 ft. condenser. 

Reason for Successful Welds. In connection with, the 
work just described, the Wilson people claim that their success, 
arid the uniformity of their welds, was made possible because 
their apparatus enables the welder to control his heat at the 
point of application. In welding there is a critical temperature 
at which steel can be worked to give the greatest tensile 
strength, and also ductility of metal. By raising the heat 
15 or 20 amp. above this critical amperage a fracture of the 




"Fio. 117. Welded Steel-Plate Condenser. Xo Rivets in Its Construction. 

Size 4 X 7 Ft. 

weld will show segregation of carbon and slag pockets, which, 
of course, weakens the weld. If the amperage is decreased 
from, the critical temperature, a fracture of the weld will show 
tliat the metal has been deposited in globules, with many voids, 
which proves that the weld has been made with' insufficient 
lieat. This shows, they claim, that with a fluctuating amperage 
oi" voltage, it is impossible to obtain uniformly high-grade 
welds. 

In addition to their apparatus they use special electrodes 
for various jobs. One electrode is composed of a homogeneous 
alloy combined with such excess of manganese as will com- 
pensate for losses while passing through the electric arc, thus 



EXAMPLES OF ARC-WELDING JOBS 



139 



insuring a substantial amount of manganese in the welded joint 
which is essential to its toughness. They also claim to have 




FIG. 118. Welded Locomotive Frame. 




FIG. 119 Built Up Pedestal Jaw. 

a manganese copper alloy welding metal electrode which is 
composed of iron homogeneously combined with such an ex- 
cess of manganese and copper over the amount lost in the 



140 



ELECTRIC WELDING 



arc as will insure to the welded joint a substantial additional 
degree of toughness and ductility. 

Their special electrodes run in grades, corresponding in 
sizes to the gage numbers of the American Steel and Wire 
Co. 's table. Grade 6 is for boiler work; grade 8 can be 
machined ; grade 9 is for engine frames, etc. ; grade 17 is for 
filling castings and grade 20 is for bronze alloys, bells, etc. 
The tensile strength of welds made with these electrodes is 




FIG. 120. At Work on a Locomotive Frame. 

given as from 40,000 to 60,000 Ib. The wire furnished is usually 
gage 9, approximately 5 / 32 in- in diameter. This is shipped 
in coils of about 160 Ib. No fluxes are used with any of these 
electrodes. 

Locomotive Work. The railroad shops of the United States 
were among the first to xise arc welding to any extent. In 
fact, without the great amount of experimental work done in 
railroad shops, the use of the arc in the repair of the damaged 
ships by welding would have been practically impossible. 



EXAMPLES OF ARC-WELDING JOBS 



141 



In some cases of locomotive repair there is a big question 
in the minds of engineers as to whether replacement is to be 
insisted upon or welding allowed. Rules have been drafted 
by a number of railroad associations, but at present no uniform 
rules covering all cases are in existence. However, on certain 




FIG. 121. Welding Cracked Driving Wheel Spokes. 

classes of work there is no real question that welding is the 
quicker and better way. 

In Fig. 118 is shown a repair on a steel locomotive frame, 
the size of the smaller section being 5X6 in. The broken ends 
were beveled off on each side and a piece of steel bar was 
welded in between the ends, thus saving considerable time and 
electrode material. 



142 



ELECTRIC WELDING 



Fig. 119 shows how the worn face of a pedestal jaw was 
built up by means of the "plastic-arc" process. 




FIG. 122. Welding Locomotive Boiler Tubes to Back Sheet. 





FlG. 123- -Method of Welding Boiler Tubes to Sheet. 

Another frame-welding job is shown in Fig. 120. The weld 
was 3 in. high, 4^ in. wide and 4 in. deep. One man finished 
the job with a Westinghouse outfit in about 5 hours. 



EXAMPLES OF ARC-WELDING JOBS 143 

Fig. 121 shows the welding- of a locomotive cast-steel drive 
wheel. Four spokes were cracked. 

Fig. 122 shows the welding of locomotive boiler tubes to 
the back flue sheet. All of these jobs were done by the "plastie- 
arc" process, and represent a very small portion of the kinds 
of jobs that may be done in a railroad shop. 

The method of welding flue ends to the sheets as suggested 
by Westinghouse is shown in Fig. 123. 

II. A. Currie, assistant electrical engineer, New York Cen- 
tral R.R., writing in Railway Age, says: 

The saving in our locomotive shop since electric welding was installed 
can hardly be calculated and the additional mileage that is obtained from 
locomotives is remarkable. This is mainly due to the following: 

l 'A. Greater permanency of repairs. 

" B. Shorter periods in the shop, giving additional use of equipment. 

" C. Existing shop facilities permit taking care of a larger number of 
.locomotives than originally expected. Shop congestion relieved. 

"I). The use of worn and broken parts which without, electric welding 
would, be thrown in the scrap pile. 

f 'E. The time required to make repairs is much less and requires 
fewer men. 

' * P. A smaller quantity of spare parts carried in stock. 

"The following is a brief description of some of the work done on 
steam locomotives: 

"Flue and Fire Box Welding. The most important results are obtained 
by welding the boiler tubes to the back flue sheet. The average mileage 
between shopping on account of leaky flues on passenger locomotives wus 
100,000 miles. This has been raised to 200,000 miles with individual 
records of 1275,000 miles. For freight this average has been raised from 
45,000 to 100,000 miles. At the time of locomotive shortage this effect 
was of inestimable value. 

"Good results have been obtained without the use of sandblast to 
prepare the tubes and sheets. The engine is either fired or an acetylene 
torch used to burn off the oil, after which the metal is cleaned oft with a 
scraping tool. The ferrules are of course well seated and the tubes rolled 
back. The boiler is filled with water in order to cool the tubes, which 
having a much thinner cross-section than the sheets, would overheat suffi- 
ciently to spoil the weld or burn the tube. The metal is then laid on, 
beginning at the bottom of the bead and working to the top. Records 
show that the time to weld a Pacific type locomotive boiler complete is 
12 hours. 

"A variety of repair work is readily accomplished in locomotive fire- 
boxes such as the welding of crown-sheet patches, side-sheet cracks and the 
reinforcing arid patching of mud rings. Smokebox studs are also welded on. 

"Side Frames, Couplers and Wheels. Cracked main members of side 



144 ELECTRIC WELDING 

frames are restored and wearing parts built up and reinforced. Because 
of accessibility no special difficulties are encountered in this work. Formerly 
this work was chiefly done with oil welding and some acetylene and thermit 
work, but it was very much more expensive as the preparation required 
considerable effort and took a good deal of time. 

1 ' Fifty per cent of the engines passing through the shops have worn 
and broken coupler parts and pockets. By welding an average saving of 
about $15 per coupler is made. It costs about $30 in material and labor 
to replace a coupler and only $4 to repair the average broken coupler. 
The scrap value is about $5. 

"Great success has resulted from various repairs to steel wheels and 
tires* Flat spots have been built up without removing the wheels from 
the locomotives, thus effecting a great saving in time and money. Building 
up sharp flanges saves about f-in. cut off the tread, which when followed 
through means about $30 for a pair of wheels, a great increase in tire 
life and reduction in shop costs. 

"Cylinders. The most, interesting feature developed by are welding 
was the accomplishment of cast-iron welding. The difficulty in welding 
cast iron was that while the hot metal would weld into the casting, on 
cooling the strain would tear the welded portion away from the rest 
of the easting. Small studding was tried out with no success. Not until 
wrought-iron studs, proportioned to the sectional strength of the casting, 
were used did any satisfactory welds turn out. Studding of this large 
size was looked upon with distrust, as it was thought that the only weld 
was to the studding. This naturally meant that the original structure 
was considerably weakened due to the drilling. This, however, was not 
the case. The large studding was rigid enough to hold against the cooling 
strains and prevented the welds in the casting from pulling loose, thus 
adding the strength of all the welded portion to that of the studs. In 
most cases where external clearance will permit, sufficient reinforcing can 
be added to more than compensate for the metal removed in drilling for 
the studs. 

11 Perhaps more skill is required for this class of welding, but with a 
properly prepared casting success is certain. A concrete case of the economy 
effected in welding a badly damaged cylinder on a Pacific type, engine 
is as follows: 

WELDED JOB 

Cost of welding broken cylinder, labor and material $125.00 

Length of time out of service, 5 days at $20 a day 100. 00 

Scrap value of old cylinder (8,440 Ib. at 2.09 Ib.) 177.00 

Total """"$402.00 

EEPLAOBD CYLINDER 

Cost of new cylinder ready for locomotive $1 000.00 

Labor charge to replace it 150.00 

Locomotive out of service IS clays at $20 a day 360.00 

"$I^icTo6 

Less cost of welding 402.00 

Total saving "$l7ioOo 



EXAMPLES OF ARC-WELDING JOBS 145 

"Some twenty-five locomotives have been repaired in this way at one 
shop alone. 

"Many axles are being reclaimed by building up the worn parts. 
These are tender and truck axhs which arc worn on the journals, wheel 
fits and collars. The saving is about $25 per tender axle and $20 for 
truck axles. 

' ' The range of parts that may be repaired or brought back to standard 
size by welding is continually expanding. Wearing surfaces on all motion 
links and other motion work, crosshead guides, piston-rod c.rosshead fits, 
valves and valve seats, air, steam, sand and other pipes, keys, pins and 
journal boxes have all been successfully welded. 

"A large saving is effected in welding broken parts of shop tools and 
machinery. During the war this was of untold value, as in some cases 
it was out of the question to get the broken parts replaced. 

"Training of Operators. The training of arc welders is most important. 
Success depends solely on the men doing the work. They must be instructed 
in the use of the arc, the type, size and composition of the electrode 
for various classes of work and the characteristics of the various machines 
they will be called upon to use. A properly equipped school for teaching 
these matters would be a valuable adjunct for every railroad. Manufac- 
turers of equipment have recognized the importance of proper instruction 
and have equipped schools where men are taught free of charge. 

"Supervision. Co-ordinate with the actual welding is intelligent super- 
vision. The scope of the supervisors should include preparation of the 
job for the welder and general oversight of the equipment in the shop. 

"Thus the duties of the inspector might be summarized in the following 
points : 

"1. To see that the work is properly prepared for the operator. 
"2. The machines and wiring are kept in good condition. 
"3. Proper electrodes arc used. 

"4. To inspect the welds in process of application, and when finisher!. 
"5. To act as advisor and medium of interchange of welding practices 
from one shop to another. 

"In work such as flue welding and industrial processes which repeat 
the same operation, piece-work rates may be fixed. For varying repair 
jobs this method cannot be used with justice either to the operator or 
the job. 

"Bare electrodes are used almost exclusively, even for a.c. welds. 
Whenever a new lot of electrodes is received it is good practice to make 
up test-piece samples and subject them to careful tests and analysis. 

"The sizes of electrodes and uses to which they are put are shown 
in the table. 

Size Type of Work 

y s in. Flue welding. 

c / 32 in. For all repair work, broken frames, cylinders, etc. 

7 / 32 in. For building up wearing surfaces. 



146 



ELECTRIC WELDING 



"General Rules. In closing it will be well to point out a few general 
rules required to obtain satisfactory welds. 

"1. The work must be arranged or chipped so that the electrode may 
be held approximately perpendicular to the plane of welding. 
When this cannot be accomplished the electrode must be bent 
so that the arc will be drawn from the point and not the side 
of the electrode. For cast iron the studding must be properly 
arranged and proportioned. The surfaces to be welded must be 
thoroughly clean and free from grease and grit. 

"2. The proper electrode and current value must be selected for the 
work to be done. 

**3. The arc should be maintained as constant as possible. 

"4. For nearly all work the prepared surface should be evenly welded 
over and then the new surfaces welded together. 

"5. Suitable shields or helmets must be used with proper color values 
for the lenses. 




FIG. 124. Built Up Cupped Rail Ends. 

"For locomotive work a good operator will deposit an average of 
1 to 1$ Ib. of electrode per hour. The limits are from 1 to 2 Ib. High 
current values give more ductile welds, in proportion to deposited metal. 
For locomotive welding the great advantage of the arc over thermit, oil 
or acetylene welding is that preparation at the weld is all that is necessary. 
No secondary preparation for expansion of the members is necessary. This 
is the great advantage in welding side frames. " 

Considerable welding work is done in building up worn 
track parts. Fig. 124 shows the building up of cupped rail 
ends and Fig. 125 shows manganese-steel cross-over points 
built up by are welding. Such repairs have stood long and 
hard service. 



EXAMPLES OF ARC-WELDING JOBS 



147 



Other Welding Work. In the steel mills a great deal of 
welding is required to build up worn roll or pinion pods. Fig. 
126 shows a welder at work building up worn pods with a 
carbon arc and filler. Fig. 127 shows a finished job with the 




FIG. 125. Built Up Manganese Steel Cross-Over Points. 




FIG. 126. Building Up Worn Roll Pods. 

worn part outlined in white. The cost of repairing four ends 
(two pinions) was $170. The pinions cost $1,000 each. 

The way a five-ton roll housing was repaired is shown in 
Fig. 128. In this ease a heavy steel plate was bolted over 
the crack and welded as indicated. It might have been all 



148 



ELECTRIC WELDING 




EiG. 127.- J& 1 ! nish- Welded Pinion Pods. 




FiG. 128. Kepaiied 5-Ton Roll Housing. 



EXAMPLES OF ARC-WELDING JOBS 



149 





FIG. 129. Welded Blowholes and Machined Pulley. 




Fro. 330.- Method of Welding Taps Broken Off in the Hole. 



150 ELECTRIC WELDING 

right to weld direct, but in this ease, owing to the heavy duty 
required, it was thought best to play safe and use the steel 
plate. 

"Welded blowholes in the rim of a large pulley are shown 
at the left in Fig. 129. At the right the pulley is shown after 
machining. 

Broken taps may be removed if a nut is welded on as 
shown in Fig. 130. In doing work of this kind, the arc is 
struck on top of the tap and kept there until the metal is 
built up above the top of the hole. An ordinary nut is then 
laid over it and welded fast. If the arc is -kept on the tap 
the metal may run against the sides of the hole but will not 
adhere, but care must be exercised so as to not let the arc 
strike the sides of the hole. 

ELECTRIC CAR EQUIPMENT MAINTENANCE 

The growing possibilities of electric welding processes in 
connection with the maintenance of rolling r,tock and other 
railway equipment have been a source of amazement to every 
electric railway man who has come into contact with the prac- 
tice, says the Electric Railway Journal. This began with the 
repair of broken members of the various parts of electric car 
equipment and has led to its use in a still larger field, which 
includes the building lip of worn surfaces of steel parts which 
previously would have been headed for the scrap heap. The 
accompanying illustrations show some parts of electric, car 
equipment which have been reclaimed by electric welding in 
the shops of several electric railways. This work was begun 
at a time when it was very difficult to obtain railway equip- 
ment parts and it has resulted in large savings and has enabled 
the equipment to be returned to service so quickly, that tho 
work is being extended and used for defective-part repair 
which previously would not have been considered. 

The United Traction Company, Albany, N. Y., constructed 
a special concrete building for its electrical repair work a year 
ago. A separate room was built at one end of this building and 
arranged particularly for electric welding, and all important 
details were incorporated in the design to fit this room for the 
purpose to which it was to be put. The building is a concrete 
structure throughout and the floor of the welding room is also 



EXAMPLES OF ARC-WELDING JOBS 



151 



of concrete. In dimensions this room is about 10 ft.XSO ft. and 
it is entirely inclosed and separated from the rest of the 
building. 

As a safety precaution no one is allowed to enter the weld- 
ing room while work is in progress. Two observation windows 
are provided on either side of the entrance door, in which 
colored glass has been installed as a protection to the eyes of 
the observer. Any one having business in the welding room 




FIG. 131. G. E. Portable Arc Welding Outfit. 

can see when welding work is being done and thus avoid the 
danger of any harmful effect from the light of the arc. 

The equipment at present in use in the welding room con- 
sists of a General Electric motor-generator set and an oxy-acety- 
leiie welding outfit, a welding table, convenient holders, masks 
and other welding equipment, and a chain hoist which travels 
on an I-beam the length of the room and also outside the 
entrance to pick up heavy work and facilitate the handling of 
heavy parts. Since the installation of this equipment the 
General Electric Company has developed a self regulating 
welding generator which constitutes a part of its single-operator 



152 



ELECTRIC WELDING 



metallic electric arc welding equipment. This can be either 
stationary or portable and as it is self-contained it makes a 
very desirable combination. The generator has a two-pole 
armature, in a four-pole frame, with commutating poles, and 
generates sixty volts, open circuit. Bucking the shunt field 
is a series field, with taps brought out for different welding 
currents. As current flows from the main brushes through 
the series field windings it reduces the generator voltage to 




FIG. 132. G. E. Generator Direct Connected to Motor, with Control 
Panel and Starter. 

the proper welding value. Figs. 131 and 132 show two types 
of G. E. equipment. 

One of the most important operations and one which shows 
far 'reaching economies in the work undertaken by the United 
Traction Company is the building up of worn armature shafts, 
as shown in Figs. 133 and 134. The pinion ends of the shafts 
were " chewed up" due to the wear of the keyways for the 
pinions. The defective ends of the shafts which were to be 
repaired were carefully cleaned of all oil and dirt and sufficient 
metal was welded 011 so that the shafts could be re-machined 



EXAMPLES OF ARC-WELDING JOBS 



153 



d re-threaded. A large number of these armatures were all 
jht except for the damage to the keyways, so that they 
re returned to service as soon as the shafts were re-machined 




FIG. 133. Worn Armature Shafts Before Welding. 




FiG. 134. Armature Shafts After Welding. 

d fitted. Others had damaged coils or grounded insulation 
d where it was necessary to re-wind an armature this was 
Dipped before the welding operations took place. For weld- 



154 



ELECTRIC WELDING 



ing operations of this character where a large amount of work 
is to be done which is similar in character the General Electric 
Company has developed an automatic welding machine 
described elsewhere. Its chief advantage lies in the increase 




in speed which is possible and the uniformity of welds which 
results. In the work done at Albany the building up and 
re-machining of the shafts cost from $3 to $4 each, which was 
only about one-tenth of the cost of a new shaft. As local 



EXAMPLES OF ARC-WELDING JOBS 



155 



conditions as to labor costs as well as the cost of energy vary 
to quite an extent detailed costs for the various operations 
arc not included, but on roads which are performing this work 
and which have actual data regarding the purchase cost of 
the various parts, the savings which result offer convincing 
proof of the economies which can be effected with the use of 
electric arc welding. 

Fig. 135 shows a pile of motor eases in the yards of the 
Tinted Traction (Company, lie-fore Hie advent of the welding 
equipment many of these motor shells were intended for scrap 




jyiG. I'M').- Repaired Goar-Gaso Suspension Ann. 

due to various breakages and excessively worn purls. By the. 
use of the welding equipment a large proportion of these have 
already been reclaimed. 

The method employed in welding broken Ings or broken 
ends of motor- shells consists first in fitting the broken parts 
together and lining them up in their correct, position. The. 
piec.es are then welded at a few points so as to hold the broken 
parts in position and, where necessary, the fracture, is cut out 
"V" shape to provide additional space for the welding metal. 
Much of the success which has been obtained in this class of 
work at Albany is attributed to the use of studs for inter- 



156 



ELECTRIC WELDING 



locking the metal which is added to the broken parts. Holes 
for the f-in. studs are drilled and tapped at several points 
adjacent to the break and the studs are so inserted as to 
extend above the motor shell to about the same height as the 
thickness of the additional metal to be added. The deposited 




FIG. 137. Broken Cast-iron Motor Shell and Axle Housings Repaired by 
Electric Welding (Case Broken in Twelve Pieces). 

metal is then allowed to bridge over these studs in welding 
and so obtains additional support which helps to strengthen 
the weld. In the illustration Fig. 136 showing repairs made 
to a broken gear-ease suspension arm, one of these studs can 
be seen projecting from the casting. 



EXAMPLES OF ARC-WELDING JOBS 



157 



As an example of what can be accomplished, in repairing 
3ken shells, the illustration Fig. 137 showing a welded end 
a motor shell alongside a lathe, is an extreme case. This 
>tor shell was broken in twelve pieces and from the illus- 
ition it will be seen that nearly the entire end was welded. 
Another record job made in the shop of the United Traction 
mpany was the welding of a truck bolster. The car, under 
ich was a truck with a broken bolster, was brought to the 
)p and placed on a track adjacent to the welding room. 





FIG. 138. FIG. 139. 

FIG. 138. Wheel Turned Down Ready for Welding. Note 

Thinness of Flange. 
FiG. 139. Flange Built Up Ready to Be Shaped in Wheel Lathe. 

3 car body was jacked up and the bolster was repaired 
approximately eight hours. The work was started at 9 
lock after the morning rush hour and the car was ready 

service again at 5.15 P.M. 
In addition to the class of work illustrated as being done 

the United Traction Company other interesting work is 
orted from, various electric railways showing what has been 
omplished. The Spokane & Inland Empire Eailroad has 
ic some work in reclaiming wheels with sharp flanges, 
ree views are given to illustrate the methods used. The 



158 



ELECTRIC WELDING 



first of these, Fig. 138, shows a wheel with the flange turned 
down ready to receive new metal. The second Fig. 139 shows 
the flange with a new layer of welded metal. The third, Fig. 
140, shows the finished wheel after it has been machined. After 
the new metal has been added the flange is merely shaped up 
with a forming tool. It is left quite rough in some cases, but 
as the practice has always been to put on new brake shoes 
when the wheels are repaired, the company has had no difficulty 
in wearing down the tread to a smooth contour. 

A number of steam railways arc at present reclaiming all 
of their cold rolled steel wheels which are slid flat or have 




PIG. 140. Finished Wheel Ready for Service. 

flaked-out places, as well as those with sharp flanges. This 
operation creates quite a saving in itself as often the car is 
merely placed over the drop pit and the work can then be 
taken care of with the car fully equipped. By this method 
the car is withheld from service but a short period. In the 
welding of sharp flanges it is not contended by those who have 
had extended experience that the metal deposited will give 
the life of the parent material, but they agree that savings 
are created as a result of maintaining the car in service until 
such time as it is necessary to shop it for major repairs. 

Another example of reclaiming electric car equipment is 
shown in, the repairs to gear cases, Fig. 141. These are a 



EXAMPLES OF ARC-WELDING JOBS 



159 



fair sample of the repairs that are frequently found necessary. 
In this case patches are made of No. 10 sheet iron. In welding 
these patches on, the operator first determines the size of the 
patch and outlines it with chalk on the old case. He then 
builds up a layer of metal just outside the chalk mark. The 
patch is then laid on and welded to a layer of metal. In 
this way a tight and secure joint is made. As gear cases are 
frequently covered with oil when they are brought in for 
repairs, they should be cleaned off as much as possible. In 
making a patch that requires a bend, as in the case illustrated, 
the operator first welds the patch to the bottom of the case, 
then heats the patch and bends it into shape. 

Split Gears Made Solid, Some electric railways which have 




FlG. 141. Gear Cases with Patches Welded On. 

split gears have found it advisable to change these to solid 
gears by welding and then to press them on the axles. Fig. 
142 shows a gear which is being welded in this manner and 
Pig. 143 an axle which has been built up so as to increase 
the gear seat. The method employed in welding the gears 
consists, first, of cutting a "V" along the joint of the gear 
down to the bolts with a carbon electrode. The operator then 
builds up with new metal and welds each bolt and fills up 
the old keyways. This bore is then re-machined and a new 
keyway is cut. Broken teeth in gears are also easily repaired 
by welding. 

Another use of welding which has been of benefit to electric 
railways is in the maintenance of housings for the bearings 
of railway motors. Constant vibration and heavy jarring 



160 



ELECTRIC WELDING 



causes the fit in the motor frame to become badly worn and 
many railways have used shims to take up this wear. A small 
layer of metal deposited by the electric arc and then machined 
to the desired dimensions provides a more serviceable job than 




FIG. 142. 



Fro. 143. 



FiG. 142. Welding Split Gear to Make a Solid One. 
FIG. 143. Axle Enlarged by Welding. 

that of the shims, and when a tight fit is once secured, the 
wear is eliminated. 

The filling in of bolt holes in various parts of the car 
equipment is another use which is showing far-reaching results. 
Heavy duty and constant vibration cause the holes to become 
worn, and the bolts then readily become loose and often fall 



EXAMPLES OF ARC-WELDING JOBS 



161 



out. The filling in of these holes and their re-drilling takes 
very little time and the cost is extremely low. 

Some other welding operations which have been carried 
out with success are these: side bearings which have become 




FIG. 144. Crankshaft with Break Cut away for Welding. 






PIG. 145. Completed Weld Before Trimming. 

badly worn have been built up, brakeshoe heads and hangers 
have been welded and truck side frames have been repaired 
in numerous cases. A large number of uses for electric welding 
are constantly presenting themselves to all railways. Enough 
instances have been cited to demonstrate the fact that the art 



162 ELECTRIC WELDING 

of welding lias greatly increased the resources available for 
lengthening the life of equipment. 

ELECTRIC WELDING A SIX-TON CRANKSHAFT 

A six-ton crankshaft in. the plant of the Houston Ice Co., 
Houston, Tex.,, broke through at one of the webs. As there 
was no means at hand to repair the break, the crankshaft 
was shipped to the Vulcan Iron Works, Jersey City, N. J., 
where it was electrically welded by the Wilson plastic-arc 
process. 

The broken web, cut away preparatory to welding, is shown 
in Fig. 144, and the finished weld in Fig. 145. Owing to the 
size of the shaft, great care had to be exercised in keeping 
it in proper alignment. Mg. 146 shows it leveled and clamped 
to a large surface plate. A straight-edge is shown laid across 
the webs to assist the operator in judging and keeping the 
alignment. 

A big feature in electric welding of this kind is that owing 
to the intense heat of the arc, no preheating is required as in 
using other methods. This, of course, greatly reduces the time 
required to complete a repair of this kind. 

ARC-WELDING HIGH-SPEED TOOL TIPS 

One large manufacturer has installed a Westinghouse arc- 
welding equipment for the sole purpose of making tools for 
turning heavy work. Ordinarily these tools are made from 
high-speed steel, and cost about $12 each. This manufacturer 
uses high-speed steel for the tip of the tool only, welding 
it to a shank of carbon or machine-steel, as shown in Fig. 147, 
and in this manner the tools arc produced at a cost of $2 
to $4. 

For several weeks this plant has been turning out 240 
welded tools a day, the men working in shifts of four, which 
is the capacity of this outfit. 

The equipment consists of a 500-amp. arc-welding motor 
generator with standard control panel, and three outlet panels 
for metal-electrode welding, and one special outlet panel for 
the use of either metal or graphite electrodes. The special 
panel is intended to take care of special filling or cutting 



EXAMPLES OF ARC-WELDING JOBS 



163 




fcUO 



O 

w 



o 

! 

CO* 



164 



ELECTRIC WELDING 



processes that may be necessary, but ordinarily it is used in 
the same manner as other panels for making tools. These 
panels are distributed about the shops at advantageous points. 
For toolmaking, which involves the hardest grades of steel, 
a preheating oven is used, not because it is necessary for mak- 
ing a perfect weld, but because otherwise the hard steel is 
likely to crack from unequal cooling and also because pre- 




FIG. 147. Welding High-Speed Tips Onto Mild Steel Shanks. 

heating makes it easier to finish the tool after the welding 
process has been completed. For ordinary arc welding opera- 
tions the preheating oven is never used. 

ELECTRICALLY WELDED MILL BUILDING. 

A small all-welded mill building was erected in Brooklyn 
in 1920 for the Electric "Welding Co., of America, by T. 
Leonard MacBean, engineer and contractor. The structure is 
about 60 X 40 ft., and has four roof trusses of 40-ft. span 
supported on 88-in. H-beam columns fitted with brackets for a 
five-ton traveling crane. In its general arrangement the struc- 
ture follows regular practice, but the detailing is such as to 
suit the use of welding, and all connections throughout are 
made by this process. A considerable advantage in cost and 
time is claimed for the welded connections, but in the present 



EXAMPLES OF ARC-WELDING JOBS 165 

instance the determinative feature was not cost economy so 
much as the fact that the fabricated work could be obtained 
more quickly by buying the plain steel members and cutting 
and welding them at the site instead of waiting for bridge shop 
deliveries. 

The roof was designed for a total load of 45 Ib. per sq. ft., 
of which about 30 Ib. represents live load. Each truss weighs 
1,400 Ib. The chords are 4X5X|-in. tecs, while the web mem- 
bers are single 3X2X-in. angles. On the trusses rest 10-in. 
15-lb. channel purlins spanning the 20-ft. width of bay. The 
columns are 8x8-in. H-beams, 19 ft. high, and the crane bracket 
on the inner face of the column is built up of a pair of rear 
connection angles, a pair of girder seat angles, and a triangular 
web plate, as one of the views herewith shows. Base and cap 
of the columns are made by simple plates. 

All material was received on the job cut to length. A 
wooden platform, large enough to take a whole truss was 
built as a working floor and the chord members were laid 
down on it in proper relative position to form a truss when 
connected. The top chord was made of a single length of tee, 
bent at the peak point after a triangular piece was cut out 
of the stem. At the heel points of the truss the stem of the 
top-chord tee was lapped past the stem of the bottom chord 
tee, and when the two members were clamped together the 
contact scams were welded; the seam 'of the stem at the peak 
was also welded shut. Then the web members were placed 
in position and clamped, and their connections to the chord 
welded. The metallic-electrode arc process was used and 
various welded parts arc shown in Fig. 148. 

Loading Tests. When the plans for the building were sub- 
mitted to the Department of Buildings, Borough of Brooklyn, 
the proposal to weld the connections was approved only with 
the stipulation of a successful load test before erection. This 
test was carried out March 20. Two trusses were set up at 
20-ft. spacing and braced together, purlins were bolted in 
place, and by means of bags of gravel a load of 48 tons was 
applied. This was sufficient to load the trusses approximately 
to their elastic limit. No straining or other change was observ- 
able at the joints, and the test was considered in every respect 
successful. The deflection of the peak, 0.0425 ft., did not 



166 



ELECTRIC WELDING 




EXAMPLES OF ARC-WELDING JOBS 167 

ange during 48 hours, and upon removal of the load at the 
d of that period a set of less than 0.01 ft, was measured. 

Speed of Arc Welding. In a paper read before the Ameri- 
i Institute of Electrical Engineers, New York, Feb. 20, 1919, 

M. Hobart says: 

All sorts of values are given for the speed, in feet per hour, with 
ich various types of joints can be welded. Operators making equally 
>d welds have widely varying degrees of proficiency as regards speed. 
y quantitative statement must consequently be of so guarded a character 
to be of relatively small use. In general, and within reasonable limits, 
speed of welding will increase considerably when larger currents arc 
ployed. It appears reasonable to estimate that this increase in speed 
1 probably bo about 25 to 35 per cent for high values of current. This 
reasc is not directly proportional to the current employed because a 
later proportion of time is taken to insert new electrodes and the operator 
working under more strenuous conditions. Incidentally, the operator 

employs the larger current will not only weld quicker but the weld 

1 have also better strength and ductility. 

On this point Mr. "Wagner writes as follows: 

I would not say that speed in arc welding was proportional to the 
rent used. Up to a certain point ductility and strength improve with 
reased current, but when these 1 conditions are met, we do not obtain 
i best speed due to increased heating zone and size of weld puddle, 
ced may fall off when current is carried beyond certain points. 

In a research made by William Spraragen for the Welding Research 
b-Committee on several tons of half-inch-thick ship plate, the average 
,e of welding was only two feet per hour. Highly skilled welders were 
ployed, but they were required to do the best possible work, and the 
ids of joints and the particular matters under comparison were very 
:icd and often novel. 

However, in the researches carried on by Mr. Spraragen it was found 
it about 1.9 11). of metal was deposited per hour using a 5 / 32 -in. bare 
ctrode and with the plates in a flat position. The amount of electrodes 
id up was about 2.7 Ib. per hour, of which approximately 1(5.5 per cent 
s wasted as short ends and 13 per cent burnt or vaporized, the remainder 
ing deposited at the speed of 1.9 Ib. per hour mentioned above. 

For a 12-ft.-cube tank of J-in. thick steel welded at Pittsfield, the 
jed of welding was 3 ft. per hour. The weight of the steel in this 
ik was 16,000 Ib. and the weight of electrode used up was 334 Ib. of 
ich 299 Ib. was deposited in the welds. The total welding time was 
5 hours corresponding to using up electrodes at the rate of just 2 Ib. 
t* hour. The total length of weld was 501 ft., the weight of electrode 
xl up per foot of weld thus being 0.60 Ib. The design of this tank 
nprised eighteen different types of welded joint. Several different 



168 ELECTRIC WELDING 

operators worked on this job and the average current per operator was 
150 amp. 

For the British 125-ft.-long Cross-Channel Barge for which the shell 
plating was composed of y 4 -in. and */w-m. thick plates, described in H. 
Jasper Cox's paper read before the Society of Naval Architects on Nov. 
15, 1918, and entitled "The Application of Electric Welding to Ship Con- 
struction/ 7 it is stated that: il After a few initial difficulties had been 
overcome, an average speed of welding of 7 ft. per hour was maintained 
including overhead work which averaged from o to 6 ft. per hour." 

In a report appearing on page 67 of the minutes and records of the 
Welding Research Sub-Committee for June 28, 1918, 0. A. Payne, of the 
British Admiralty, states: "A good welder could weld on about one pound 
of metal in one hour with the No. 10 Quasi-Arc electrode, using direct 
current at 100 volts. An electrode containing about 1A oz. of metal is 
used up in about 3 minutes, but this rate cannot be kept up continously. " 

The makers of the Quasi-Arc electrode publish the following data for 
the speed of arc welding in flat position with butt joints, a 60-deg. angle 
and a free distance of J-in. 



Thickness 
of Plates 
X in. 


Speed in Feet 
per Hour 


i in. 


is 


i in 


() 


1 in ... 









I cannot, however, reconcile the high speed of welding .jrin. plate 
published in this report as 6 ft. per hour, with the report given above 
by the British Admiralty that a good welder deposits 1 Ib. of metal per 
hour with the Quasi-Arc electrode. If the rate given by the manufacturer 
is correct, it would mean that about four pounds of metal were deposited 
per hour. On this basis the rate must have been computed on the time 
taken to melt a single electrode and not the rate at which a welder could 
operate continuously, allowing for his endurance and for the time taken 
to insert fresh electrodes in the electrode holder and the time taken for 
cleaning the surface of each layer before commencing the next layer. 
From his observations I am of the opinion that a representative rate for 
a good welder lies about midway between those valuon given respectively 
by Mr. Payne, and by the makers of the Quasi -An? electrode, say for 
-in. plates some 2 Ib. per hour. This, it will be observed, agrees with 
Mr. Spraragen's experience in welding up some (> tons of ^-in. ship plate 
with a dozen or more varieties of butt joint and Mr. Wagner's .results with 
an 8-ton tank. Even this rate of 2 Ib. per hour is only the actual time 
of the welding operator after his plates are clamped in position. This 
preliminary work and the preparation of the edges which is quite an under- 
taking, and requires other kinds of artisans, accounts for a largo amount 
of time and should not be under-estimated. 

The practice heretofore customary of stating the speed of welding iu 



EXAMPLES OF ARC- WELDING JOBS 169 

feet per hour has led to endless confusion as it depends on type of joint, 
height of weld and various details. A much better basis is to express 
the speed of welding in pounds of metal deposited per hour. Data for 
the pounds of metal deposited per hour are gradually becoming quite definite. 
The pounds of metal per foot of weld required to be deposited can be 
readily calculated from the drawings or specifications. With the further 
available knowledge of the average waste in electrode ends and from other 
causes, the required amount of the electrode material for a given job can be 
estimated. 

Suitable Current for Given Cases. For a given type of weld, for 
example, a double V-weld in a ^-in. thick ship plate, it was found that 
in the summer of 1918, while some operators employed as low as 100 amp., 
others worked with over 150 amp. Some, in making such a weld, employed 
electrodes of only -in. diameter and others preferred electrodes of twice 
as great cross-section. For the particular size and design of weld above 
mentioned, the Welding Research Sub-Committee had welds made with 200 
to 300 amp. The conclusion appears justified that the preferable current 
for such a weld is at least 200 amp. If the weld of the -Km.-thiek plate 
is of the double-bevel type, some 50 amp. less current should be used for 
the bottom layer than is used for the second layer, if two layers arc 
used. For -in.-thiek plates, the most suitable welding current is sonic 
300 amp. This is of the order of twice the current heretofore usually 
employed for such a weld. 

Mr. Wagner writes: 

We have made a number of tests to determine the effect of varying 
current on the strength of the weld. Tests were made on a J-in. plate 
with current values as follows: 80, 125, 150, 180, 220, 275 and 300 amp. 
These tests show improvement in the tensile strength and bending qualities 
of welds as the current increases. The speed of welding increases up to a 
certain point and then decreases. 

Effect on Arc Welding of Voltage Employed. We have made a number 
of tests to determine the influence of variable voltages on the strength 
and character of electric welds. The experiments were made welding Hn. 
plate with 150 amp. held constant and voltage varying as follows: 40, 75, 100, 
125, 150, 200 and 225 volts. This test demonstrates that there is no material 
difference in the tensile strength, bending qualities or the appearance of 
the welded- in material. There is this advantage, however, in the higher 
voltage, that variations in the strength of the arc do not materially affect 
the value of the current. A curve-drawing ammeter was installed on 'the 
welding circuit which showed variations in current at 75 volts, but at 150 
volts the current curve was practically a straight line. 

Preferable Size of Electrode. On certain railways, a single diameter 
of electrode is employed independently of the size or shape of the plates 
or parts being welded. The experience of other people leads them to make 
use of several different sizes of electrodes according to the size of the 
job and the type of joint. Present British practice appears to be to use 



170 ELECTRIC WELDING 

such a size of electrode as to have a current density of some 4,000 to 
6,000 amp. per square inch. The investigations of the Welding Research 
Sub-Committee indicate that at least 10,000 to 12,000 amp. per square inch 
is suitable for electrodes of y s -in. and 5 / 32 -in. diameter and well up toward 
10,000 amp. per square inch for electrodes of 3 /i 6 -in. and %-in. diameter. 



CHAPTER IX 
PHYSICAL PROPERTIES OF ARC-FUSED STEEL 

The work of the Bureau of Standards in investigating the 
physical properties of arc-fused steel, was described in Chemical 
and Metallurgical Engineering, by Henry S. Rowdon, Edward 
Groesbeck and Louis Jordan. This was by special permission 
of Director Stratton. The article was substantially as follows: 

During the year 1918 at the request of and with the co- 
operation of the welding research sub-conimitt.ee of the 
Emergency Fleet Corporation an. extensive, program was outlined 
by the Bureau of Standards for the study of arc-welding. 
Due to changed conditions, however, at the close of the year 
1918, the original program was modified and shortened very 
considerably. In drawing up the modified program, it was 
decided to make the study of the characteristic properties 
of the fuscd-in metal the primary object of the investigation, 
the study of the merits of the different types of electrodes 
being a secondary one. Since the metal of any weld produced 
by the electric-arc fusion method is essentially a casting, as 
there is no refinement possible as in some of the other methods, 
it is apparent that the efficiency of the weld is dependent upon, 
the properties of this arc-fused metal. Hence a knowledge of 
its properties is of fundamental importance in the study of 
electric-arc welds. 

Preliminary Examinations of Electric- Arc Welds. Numer- 
ous articles have appeared in technical literature bearing 1 on 
the subject of electric-arc welding. Most of these, however, 
are devoted to the technique and comparative merits of the 
method, manipulations, equipment, etc., rather than to the 
study of the characteristics of the metal of the weld itself. 
The information on this phrase of the subject is rather meager. 

A considerable number of examinations were made of welds 
'prepared by means of the electric-arc process and representa- 
tive of different conditions of welding. 

171 



172 ELECTRIC WELDING 

Most of these were of a general miscellaneous nature and 
the results do not warrant including a description of the 
different specimens here. One series of particular interest, 
however, may well be referred to in detail. As part of this 
study the welding research sub-committee submitted to the 
Bureau of Standards a number of welds of ship-plate repre- 
sentative of English practice for examination, some of which 
were considered as very superior examples of welding as well 
as others of a decidedly inferior grade. In Tables VII and 
VIII are given the results obtained by the mechanical tests 
made upon these specimens. The welding was done by skilled 
operators by means of special brands of electrodes (welding 
pencils), the trade names of which, however, have been omitted 
from the tables. The specimens were examined microscopically 
very carefully, in addition to the mechanical tests made. The 
results are not included, however, as the structural features 
of the material did not differ from those to be discussed in 
another chapter. The results of the mechanical tests given 
are of value in that they are indicative of the average 
mechanical properties which should be expected in electric-arc 
welds of satisfactory grade for the shape and size of those 
examined. 

Method of Building' Specimens. The specimens required 
for the study of the mechanical properties of the arc-fused 
metal were prepared for the most part at the Bureau of 
Standards, direct current being used in the operation. The 
apparatus used is shown diagrammatically in Fig. 149. By 
means of the adjustable water rheostat the current could be 
increased progressively from 110 to 300 amp. By the use of 
automatic recording instruments the voltage and current were 
measured and records were taken at intervals during the 
preparation of a specimen. The values of current given in 
the tables are those which were desired and were aimed at. 
The average deviation from this value as recorded by the 
curves was approximately 5 amp. The value of .the current 
at the instant "the arc was struck" was of course many times 
the normal working value used during the fusion. 

Since the investigation was concerned primarily with the 
properties of the arc-fused metal, regular welds were not made. 
Instead the metal was deposited in a block large enough to 



PHYSICAL PROPERTIES OF ARC-FUSED STEEL 173 







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174 



ELECTRIC WELDING 



permit a tension specimen (0.505 in. diameter, 2 in. gage length) 
to be machined out of it. Although the opinion is held by 
some welders that the properties of the metal of an arc-weld 
are affected materially by the adjacent metal by reason of 
the interpenetration of the two, it was decided that the change 
of properties of the added metal induced by the fusion alone 
was of fundamental importance and should form the basis 
of any study of arc-welding. The method adopted also per- 
mitted the use of larger specimens with much less machining 




FIG. 149. Arrangement of Apparatus for Welding. 

than would have been possible had the metal been deposited 
in the usual form of a weld. 

In the first few specimens prepared (ten in number) the 
metal was deposited by a series of "headings" inside a 1-J-in. 
angle iron. The tension specimens cut from the deposited 
metal were found to be very inferior and entirely unsuitable 
for the study. This was largely on account of the excessive 
overheating which occurred as well as the fact that a relatively 
"long arc" was necessary for the fusion in this form. Because 
of the very evident inferiority of these specimens, the results 
of the mechanical tests made are not given in the tables. 
The method of deposition of the metal was then changed to 



PHYSICAL PROPERTIES OF ARC-FUSED STEEL 175 

that shown in Fig. 150. This method also had the advantage 
in that the amount of necessary machining for shaping the 
specimens for test was materially reduced. The block of arc- 



Side View 



End View 
FIG. 150. Method of Formation of the Blocks of Are-Fused Metal. 

fused metal was built up on the end of a section of f-in. 
plate of mild steel (ship plate) as shown. When a block of 
sufficient sixe had been formed, it, together with the portion 




FIG. 151. -Block of Arc-Fused Metal with Tension Specimen Cut from It. 
Approximately Half Natural Size. 

of the steel plate immediately beneath, was sawed off from 
the remainder of the steel plate. The tension specimen was 
turned entirely out of the arc-fused metal. No difficulty what- 
ever was experienced in machining the specimens. Fig. 151 



176 ELECTRIC WELDING 

shows the general appearance of the block of fused metal as 
well as the tension specimen turned out of it. 

In general in forming the blocks, the fused metal was 
deposited as a series of "beads" so arranged that they were 
parallel to the axis of the tension specimen which was cut 
later from the block. In two cases, for purposes of comparison, 
the metal was deposited in "beads" at right angles to the 
length of the specimen. In all the specimens, after the deposi- 
tion of each layer, the surface was very carefully and vigor- 
ously brushed with a stiff wire brush to remove the layer of 
oxide and slag which formed during the fusion. There was 
found to be but little need, to use the chisel for removing this 
layer. 

Two types of electrodes were used as material to be fused. 
These differed considerably in composition as shown in Table 
IX, and were chosen as representative of a "pure" iron and 
a low-carbon steel. The two types will be referred to as "A" 
and "B" respectively in the tables. They were obtained in the 
following sizes: Y 8 , 5 /3 2 , Vio and V 4 in. ("A" electrode 5 /i 
in.). It was planned to use the different sizes with the follow- 
ing currents: V* * n - ?5, HO and 145 amp.; 5 / 3:J in. 145, 185 
and 225 amp.; s / w in. 185, 225 and 260 amp.; Y 4 in. ( 5 / ltt 
in.) 300 amp. The electrodes were used both in the bare 
condition and after being slightly coated with an oxidizing 
and refractory mixture. For coating, a "paste" of the follow- 
ing composition was used: 15 g. graphite, 7.5 g. magnesium, 
4 g. aluminium, 65 g. magnesium oxide, 60 g. calcium oxide. 
To this mixture was added 120 c.c. of sodium silicate (40 deg. 
Be.) and 150 c.e. of water. The electrodes were painted on 
one side only with the paste. The quantity given above was 
found to be sufficient for coating 500 electrodes. The purpose 
of the coating was to prevent excessive oxidation of the metal 
of the electrode during fusion and to form also a thin protective 
coating of slag upon the fused metal. 

Tension specimens only were prepared from the arc-fused 
metal. It is quite generally recognized that the tension test 
falls very short in completely defining the mechanical proper- 
ties of any metal; it is believed, however, that the behavior 
of this material when stressed in tension is so characteristic 
that its general behavior under other conditions of stress, 



PHYSICAL PROPERTIES OF ARC-FUSED STEEL 177 



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178 



ELECTRIC WELDING 



particularly when subjected to the so-called dynamic tests 
i.e., vibration and shock can be safely predicted from the 
results obtained. In order to supplement the specimens made 
at the Bureau a series of six were also prepared by one of 
the large manufacturers of equipment for electric welding to 
be included in the investigation. These are designated as 
"C" in the tables. 

In Table IX it will be noted that the general effect of 
the fusion is to render the two materials used for welding 
pencils more nearly the same in composition. The loss of 
carbon and of silicon is very marked in each case where these 
elements exist in considerable amounts. A similar tendency 
may be noted for manganese. The coating with which the 
electrodes were covered appears to have but little influence, 
if any, in preventing the oxidation of the carbon and other 
elements. 

TABLE X RELATION BETWEEN NITROGEN-CONTENT AND CURRENT 

DENSITY * 



Size of 








Elee.- 
trode, In 


Amperes Cunent NitrogenContent (Per Cent!) 
(Approx) Density "A" Spec. "B" Spec. "C" Spec. Average 


t 


"0 9,000 {g-}^ 


0.152 \ .... 
O.I4I 


138 


1 


145 11,800 {g]^ ; . 


0.132 
I35 


126 


& 


\Aa i inn } 0- 140 
145 7,600 ( o.l21 


124 
0.122 


127 


A 


, ft c q zcn / 123 

185 9,650 \ 0.119; 


121 
163 
I32J 


131 


A 


225 11.700 \\\\\^ 


0. 117 \ 
123 / 


* 
+ 


h 


175 9,100 


..... (0.133 


b 






\ 098 




A 


185 6,700 J;j|6 $ 


0. 119 \ 
0.106 / 


120 


A 


2?5 8,150 J;J3| 5 


0.111 
0.1081-1 


120 


A 


260 9,400 J 3 3 3 


0.112 \ 
0.094 j 


118 


A 


300 3,900 0-}}* 





114 



* Credit due J. R. Cain. 

t Average 9! two determinations. 

t Included in average for C-D 1 1 ,800. 

Coated electrodes. 

6 Included in average for C-D 9,000. 

o Average of 9 determinations. 



The most noticeable change in composition is the increase 
in the nitrogen content of the metal. In general the increase 
was rather uniform for all specimens. In Table X are sum- 
marized the results of the nitrogen determinations together 



PHYSICAL PROPERTIES OF ARC-FUSED STEEL 



179 



TABLE XI TENSILE PROPERTIES OF ELECTRODES 



*- Electrode- 
Size, 
In. 


Ulto. 
Strength, 
Lb. Sq.In. 


-Proper. 
Limit, 
Lb. Sq.In. 


Elong. 
in 2 In. 
Per Cent 


Reduct, 
Area, 
!Per Cent 


A 


& 


65,800 


39,000 


16.5 


69.2 


A 




62,100 


48.000 


9.0 


69.3 


A 




60,100 


34,500 


14.0 


66.4 


A 


& 


57,300 




15 5 


67.6 


B 


& 


88,600 


67,000 


4.5 


51. > 


B 


A 


84,700 


58,500 


7.0 


59.8 


B 


'4 


66,300 


37,500 


15.0 


61.4 


B 


i 

4 


67,900 




15 5 


62.4 



with the corresponding current density used for the fusion 
of the metal. In Pig. 152 the average nitrogen contents found 
for the different conditions of fusion are given and plotted 
against, the corresponding current density. Though no definite 
conclusion seems to be warranted, it may be said that, in 



0.170 



O.I SO 



0.130 



0.110 



0.090 



000 6000 8000 10,000 12,000 

Current Density .Amperes per Sq.In. 

FiG. 152. Relation of Current Density to Nitrogen Content in 

Arc-Fused Iron. 
Black dots represent averages. 

general, the percentage of nitrogen taken up by the fused 
iron increases somewhat as the current density increases. With 
the lowest current densities used the amount of nitrogen was 
found to decrease appreciably. 

Mechanical Properties of the Arc-Fused Metal. The 
mechanical properties of the two types of electrodes used as 
determined by the tension test are summarized in Table XL 



180 



ELECTRIC WELDING 



TABLE XII TENSILE PROPERTIES AND HARDNESS OF FIFTY SPECIMENS 
OF WELD-METAL AT THE BUREAU. (0.505-iN. DIAM. STANDARD TENSION 
BAR USED) 






Bare Electrodes 
Tensile Properties J 


o 
p. 

C 





V) 

V 

c 


d 




* 


S 


" 


S 


T3 


6 


O 


G 


a 




<N 

C 


"^ 


ca 


0> 


d 


g c* 


' 






*" 


js p3 




& -d 


I 


%n 


w 

n c 


.5 


S H 


g. 


* !S 


S 


,CQ 


>Q 




'tn 55 




5 > 


Pi 


K 


DH 


a 


A2 i 

A3 i 


110 
145 


49,850 36,600 
51.950 36,250 


25,000 
30,000 


6.0 
80 


6.5 
13.0 


108 
114 


A7 A- 


145 


47,550 




6.0 


'74 


108 


A8 A 
A9 A 
A4 A 
A5 A 
A6 A 


185 
225 
185 
225 
260 


48,100 
45,500 '.:... 
50,600 33,750 
49,150 36,250 
50,950 33,750 


29', 5 66 
22,000 
28,800 


8.0 
8.0 
5.5 
7.0 
10.5 


8.7 
9.6 
13.5 
10 
12.0 


104 

101 

105 
102 
107 


A10 1% 


300 


46,670 ..... 




12.0 


11.9 


104 V 


Covered Electrodes 


AD2 1 
AD2-D i 
AD3 1 


110 
MO 
145 


51,250 35,000 
43,000 
51,100 33,750 


25,600 
23.000 
25,000 


9.5 
5.0 

8.5 


11.0 
90 
10. '5 


103 
110 


AD3-D \ 


145 


46,250 


24,250 


7.0 


12.0 




AD7 -ft 


145 


41,750 ..... 




6.0 


66 


99 


AD7-D A 
AD8 X 
AD8-D 
AD9 i 


145 
185 

r 185 

225 


46 950 . . 


25.566 
23,250 


8.0 
6.5 
6.5 
9.5 


9.4 
5.8 
90 
10. 1 


103 
96 


44,620 . 
43 600 


46,900 


AD9-D 

AD4 ifl 


r 225 
185 


41,550 
51,200 35,000 


25,500 
30,000 


5.0 
10.5 


6. 5 

10.5 


101 


AD4-D. ^ 
AD5 -d 


r 185 

r 225 


45,700 
48.600 35,000 


25,500 
30,000 


8.5 
7.0 


11.5 
10.0 


'% 


AD5-D 5 
AD6 f 


225 

r 260 


46 250 


23,750 
31,500 


11.5 
9.0 


12.0 
9.0 


97 


47,500 34,500 


AD6-D ij 


r. 260 


50,700 




8.0 


2.8 


105 


AIMO 


t 300 


45,900 




8.5 


11.5 


98 


Bare Electrodes 


B2 
B3 
B4 * 
B5 ^ 
B6 } 


i no 

t 145 
j 145 
j 185 
J 225 


52,650 37,000 
54,500 36,000 
46,450 33,500 
49,600 34,250 
49,500 30,500 


27,000 
27,000 
26,000 
27,000 
28,000 


7.5 
12.5 
5.0 
7.5 
9.0 


1 7.5 
120 
7 
9 
5 


114 
106 
102 
10S 

no 


B7 f 
B8 J 
B9 1 s 


i 185 
225 
r 260 


47,550 
42,900 
47,500 


28,500 
18,750 
21,500 


7.5 
7.5 
12.0 


11.5 
16 2 
13 5 


95 
101 
102 


Covered Electrodes 


BD2 


} 110 


49,050 33,750 


27,500 


9.0 


12.0 


100 


BD2-D 


110 


44,400 


20,000 


6.5 


9.4 




BD3 


145 


52,100 34 $ 300 


30,500 


12.5 


16.0 


I |(j 


BD3-D 


145 


50,850 


23,500 


13.0 


17.5 




BD4 i 


r 145 


48,130 31,000 


30,500 


8.0 


10.0 


1 01 


BD4-D i 


? .145 


41,750 


21,000 


6.0 


9.5 




BD5 i 


V 185 


49,086 31,730 


29,000 


12.5 


13.0 


'97 


BD5-D i 


? 185 


47,100 . .. 


22,500 


110 


12 5 




BD6 i 


ir 225 


45,500 30,500 


25,000 


8 5 


10.5 


95 


BD7 i 


ir 185 


49,950 


24,500 


11 5 


21 5 


98 


BD7-D T> 


k 185 


51,150 


23,750 


14.5 


19 5 




BD8 3 


r 225 


41,500 


17,850 


6.0' 


12 7 


99 


BD8-D(?) T 
BD9 i? 


lr(T) 225(?) 
t- 260 


48,750 
46,350 


21,250 
24,000 


12.5 
10.0 


16.0 
15.0 


99 


Bare Electrodes 


CJ V 


*, 175 


48,650 32,650 


23,000 


12.0 


19.1 




C2 i 


J 175 


45,200 32,400 


23,000 


7.5 


16.6 




C3 i 


5 175 


49,720 32,650 


25,000 


9.0 


13.6 




C4 


I 175 


54,500 32,500 


25,000 


11.0 


17 5 


iis 


C5 , 


f 175 


50,900 32,500 


24,000 


15 


23.0 


109 


C6 4 


I 175 


50,500 33,500 


23.000 


12 


16.0 





PHYSICAL PROPERTIES OF ARC-FUSED STEEL 181 



p 

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r* r 



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II 11 = 



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182 ELECTRIC WELDING 

In Table XII are given the results of the mechanical tests 
made upon the tension specimens which were turned out of the 
blocks of metal resulting from the fusion of the elec- 
trodes. 

The specimens listed, C 19 C 2 ....C 6 are the six which were 
prepared outside the Bureau and submitted for purposes of 
comparison. It was stated that they were prepared from bare 
electrodes 5 / 32 in - diameter of type "B," containing 0.17 per cent 
carbon and 0.5 per cent manganese. 

As an aid for more readily comparing the mechanical prop- 
erties of the two types of arc-fused metal "A" and "B," the 
results have been grouped as given in Table XIII. 

The characteristic appearance of specimens after testing, 
illustrating their behavior when stressed in tension till rupture 
occurs is shown in Fig. 153. These represent two views of 
the face of the fracture, one in which the line of vision is 
perpendicular to the face, the other at an angle of 45 dog 1 ., 
together with a side view of the cylindrical surface of the 
specimen. The features shown are characteristic of all the 
specimens tested, though in some they were much more pro- 
nounced than those shown. The fracture of the specimen in 
all cases reveals interior flaws. In some of the specimens, 
however, these are microscopic and of the character to be 
discussed in a subsequent chapter on Metallography. Although 
many of the specimens (from the results of Table XII) appear 
to have a considerable elongation, it is seen from Fig. 153 
that the measured elongation docs not truly represent a prop- 
erty of the metal itself. It is due rather to interior defects 
which indicate lack of perfect union of succeeding additions 
of metal during the process of fusion. The surface markings 
of the specimen after stressing to rupture are very similar 
to those seen in the familiar "flaky steel." 

Resulting Physical Properties Depend Essentially on Sound- 
ness. It appears from the results above that, as far as the 
mechanical properties are concerned, nothing was gained by 
coating the electrodes. The results show no decided superiority 
for either of the two types of electrodes used. This may be 
expected, however, when one considers that the two are rendered 



PHYSICAL PROPERTIES OF ARC-FUSED STEEL 183 

practically the same in composition during fusion by the burn- 
ing out of the carbon and other elements. 

The results of the tension tests upon the "C" series of 




FIG. 153. Characteristic Appearance of Tension Specimen After Test. 

At top, face of fracture, viewed normally. Middle, fractured end of specimen, 
viewed at 'an angle of 45 deg. At bottom, cylindrical surface of specimen. Mag- 
nification, X 2. 

specimens which were made outside of the Bureau and sub- 
mitted to be included in the investigation, show no marked 
difference between these samples and those prepared by the 
Bureau. In all cases the results obtained in the tension test 



184 ELECTRIC WELDING 

are determined by the soundness of the metal and do not 
necessarily indicate the real mechanical properties of the 
material. 

The results of the hardness determinations do not appear 
to have any particular or unusual significance. The variations 
are of the same general nature and relative magnitude as the 
variations observed in the results of the tension test. In 
general the higher hardness number accompanies the higher 
tensile values, though this was not invariably so. As previously 
noted, specimens were prepared for the purpose of showing 
the relation between the" direction in which the stress is applied 
and the manner of deposition of the metal. The metal was 
deposited in the form shown in Fig. 151, except that the 
" beads n extended across the piece rather than lengthwise, 
hence the "beads" of fused metal were at right angles to the 
direction in which the tensional stress was applied. The results 
of the tension tests show that these two specimens (AW X and 
AW 2 ) were decidedly inferior to those prepared in the other 
manner as shown in Table XIV. 

TABLE XIV. MECHANICAL PROPERTIES OF ARC-FUSED METAL DEPOSITED 
AT RIGHT ANGLES TO LENGTH OF SPECIMEN 



Specimen 


Ult. 
Strength, 
Lb. Sq. In. 


Proportional 
Limit, 
Lb. Sq. In. 


Elongation 
in 2 in. (per 
Gent) 


Ked. of Area, 
per Cent 


AW 1 


40,450 


22,500 


6.5 


S.5 


AW 2 


39,500 


22,500 


4.0 


3.0 



Macrostructure. The general condition of the metal result- 
ing from the arc-fusion is shown in Figs. 154 and 155, which 
show longitudinal median sections, of a series of the tension 
bars adjacent to the fractured end. The metal in all of these 
specimens was found to contain a considerable number of 
cavities and oxide inclusions, these are best seen after the 
surfaces are etched with a 10 per cent aqueous solution of 
copper-ammonium chloride. In many of the specimens the 
successive additions of metal are outlined by a series of very 
fine inclusions (probably oxide) which arc revealed by the 
etching. There appears to be no definite relation between the 
soundness of the metal and the conditions of deposition i.e., 
for the range of current density used nor does either type 



PHYSICAL 



OF ABC-FUSED STEEL 186 




FIG. 154. Macro structure of Arc-Fused Metal, Type A. 

Medial Longitudinal sections of the tension bars indicated were used (Table 
XII) ; etching 1 , 10 per cent aqueous solution of copper-ammonium, chloride. Mag- 
nification, X 2. From top to bottom in order: 

ADC -A electrode; -Ho in., covered, 260 amp. 

A5 A electrode; iMe in., bare, 225 amp. 

A6 A electrode; -Ho in., bare, 260 amp. 

A3 A electrode; | in., bare, 145 amp. 

A4 A electrode; ^io in., bare, 185 amp. 



186 



ELECTRIC WELDING 



of electrode used show any decided superiority over the other 
with respect to porosity of the resulting fusion. In Pig. 156 








Fl6. 155. Maerostructure of Arc-Fused Metal, Type B. 

Medial longitudinal sections of the tension bars indicated were used (Table XII) ; 
etching, 10 per cent aqueous solution of copper-ammonium chloride. Magnification, 
X 2. From top to bottom in order: 

B4 B electrode; te in., bare, 145 amp. 
B5 B electrode; %2 in., bare, 185 amp. 
B2 B electrode; | in., bare, 110 amp. 
B3 B electrode; | in., bare, 145 amp. 
BD6 B electrode; $2 in., covered, 225 amp. 
BD4 B electrode; 5 /& in., covered, 145 ump. 

is shown the appearance of a cross-section of one of the blocks 
of are-fused metal prepared outside of the Bureau by skilled 



PHYSICAL PROPERTIES OF ARC-FUSED STEEL 



187 



welding operators. The condition of this material is quite 
similar to that prepared by the Bureau. 

The microscopic study of the material to be discussed in 
a subsequent chapter also revealed further evidence of unsound- 
ness in all three types, "A," n B" and "C." 

Discussion of Results. In any consideration of electric-arc 
welding it should constantly be borne in mind that the weld- 




FIG. 156. Macrostrueture of Arc-Fused Metal, Type C. 

Specimen Cl (Table XII), cross-section of the block of arc-fused raetal from 
which the tension bar was turned; etched with 5 per cent alcoholic solution of 
picric acid. Magnification, X 1.7. 

metal is simply metal which has been melted and has then 
solidified in situ. The weld is essentially a casting, though 
the conditions for its production are very different from those 
ordinarily employed in the making of steel castings. The 
metal loses many of the properties it possesses when in the 
wrought form and hence it is not to be expected that a fusion 
weld made by any process whatever, will have all the proper- 
ties that metal of the same composition would have when in 
the forged or rolled condition. A knowledge of the char- 



188 ELECTRIC WELDING 

acteristic properties of the arc-fused iron is then of funda- 
mental importance in the study of the electric-arc weld. 

The peculiar conditions under which the fusion takes place 
also render the metal of the weld quite different from similar 
metal melted and cast in the usual manner. It is seemingly 
impossible to fuse the metal without serious imperfections. 
The mechanical properties of the metal are dependent there- 
fore to an astonishing degree upon the skill, care and patience 
of the welding operator. The very low ductility shown by 
specimens when stressed in tension is the most striking feature 
observed in the mechanical properties of the material as 
revealed by the tension test. As explained above, the measured 
elongation of the tension specimen does not truly indicate a 
property of the metal. Due to the unsouiidness, already 
described in the discussion of the structure, the true properties 
of the metal are not revealed by the tension test to any 
extent. The test measures, largely for each particular speci- 
men, the adhesion between the successively added layers which 
value varies considerably in different specimens due to the 
unsoundness caused by imperfect fusion, oxide and other inclu- 
sions, tiny enclosed cavities and similar undesirable features. 
The elongation measured for any particular specimen is due 
largely, if not entirely, to the increase of length due to the 
combined effect of the numerous tiny imperfections which exist 
throughout the sample. 

That the metal is inherently ductile, however, is shown 
by the behavior upon bending (later to be discussed) in the 
microstructure of bent specimens. The formation of slip-bands 
within the ferrite grains to the extent which was observed 
is evidence of a high degree of ductility. It appears, however, 
that the grosser imperfections arc sufficient to prevent any 
accurate measurement of the real mechanical properties of 
the metal from being made. The conclusion appears to be 
warranted therefore that the changes of composition which the 
fusion entails, together with the unusual features of micro- 
structure which accompany the composition change are of 
minor importance in determining the strength, durability and 
other properties of the arc weld. 

In arc-fusion welds in general, the mass of weld-metal is in 
intimate contact with the parts which are being welded so that 



PHYSICAL PROPERTIES OF ARC-FUSED STEEL 



189 



it is claimed by many that because of the diffusion and inter- 
mingling of the metal under repair with that of the weld, 
properties of the latter are considerably improved. The com- 
parison shown in Table XV somewhat supports this claim. The 
nearest comparison found available with the Bureau's specimen 
are some of those of the welds designated as the "Wirt- 
Jones" series reported by H. M. Hobart. These welds were 
of the 45 deg. doublc-V type made in -J-in. ship plate ; the 
specimens for test were of uniform cross-section iXi in., the 
projecting metal at the joint having been planed off even with 
the surface of the plates and the test bars were so taken that 
the weld extended transversely across the specimen near the 
center of its length. The electrodes used were similar to those 
designated as type "B" in the Bureau's investigation. 

TABLE XV. COMPARISON OP WELDS WITH TESTS OF ARC-FUSED METAL 
PREPARED UNDER SIMILAR CONDITIONS. 



. . Bureau of Standards - 



Wirt-Jones 



S 
< 



N: 3 . 


**'? 


C i* 


fl 


O 


-J.fi- 


e 

3 a 


r/5*~* O 


5* 


s a 


/75'~~' 


O 


^i 


*"* 


& no 


52,650 


7.5 


1 


no 


45,800 


8 


i + 110 


49,050 


90 


1 


115 


58,200 


14 


*t no 


44,400 


6 5 




115 


59,400 


13 5 


Average 


. 48,700' 


7 7 


1 


120 


53,700 


7 


A '45 


46,450 . 


5 


5' 


120 


57,600 


8 5 


&* 145 


48,130 


8 


Average 




. 54,940 


10 2 


A'' 145 


41,750 
45,440 


6 3 


*L- 


150 
155 


60,900 
62,600 


8 
11 5 


ft 185 


49,600 


7 5 






61,750 


9.8 


A 185 


4Q.086 


12 5 


Average 


175 


59.800 


9 


& 185 


47.100 


II 










Average . ... 


48,395 


10 3 











* Electrodes wcro used in bare condition. 
t Electrodes were coated as previously described, those not so designated in 
this column were used bare 

Since the specimens used in work described in the fore- 
going sections were prepared in a manner quite different from 
the usual practice of arc-welding, no definite recommendations 
applicable to the latter can be made. It appears, however, 
from the results obtained that the two types of electrodes used 
i.e., "pure" iron and low-carbon steel should give very 
similar results in practical welding. This is due to the changes 
which occur during the melting so that the resulting fusions 
are essentially of the same composition. The use of a slight 



190 ELECTRIC WELDING 

coating on the electrodes does not appear to be of any material 
advantage so far as the properties of the resulting fused metal 
are concerned. Since the program of work as carried out did 
not include the use of any of the covered electrodes which 
are highly recommended by many for use in arc welding, 
particularly so, for " overhead work/' no data are available 
as to the effect of such coatings upon the properties of the 
metal resulting from fusion. Although all of the specimens 
used in the examinations were made by the use of direct 
current, it appears from the results obtained with a consider- 
able number of welds representing the use of both kinds of 
current, submitted for the preliminary examinations which 
were made, that the properties of the fused metal are inde- 
pendent of the kind of current and are influenced primarily 
by the heat of fusion. Any difference in results obtained by 
welding with alternating current as compared with those 
obtained with direct current apparently depends upon the rela- 
tive ease of manipulation during welding rather than to any 
intrinsic effect of the current upon properties of the metal. 



CHAPTER X 
METALLOGRAPHY OF ARC-FUSED STEEL 

The same authors responsible for the description of the 
investigations at the Bureau of Standards, given in the previous 
chapter, also furnished the data given in this chapter: 

Fusion welds evidently are fundamentally different from 
other types of joints in that the metal at the weld is essentially 
a casting. A preliminary study of a considerable number of 
specimens welded under different conditions confirmed the 
impression that the arc-fusion weld lias characteristics quite 
different from other fusion welds. 

In the present study, of which both the previous chapter 
and this one form a part, two types of electrodes, a "pure" 
iron called "A" and a mild steel called "B," were used, in 
the bare condition, and also after receiving a slight coating. 
With those were included a sot of similar specimens prepared 
outside of the Bureau by expert welding operators. During 
the fusion the composition of the metal of the two types of 
electrodes is changed considerably by the "burning-out" of 
the carbon and other elements, the two becoming very much- 
alike in composition. A very considerable increase in the 
nitrogen content occurs at the same time, as shown by chemical 
analysis. 

The mechanical properties of the arc-fused metal as 
measured by the tension test are essentially those of an inferior 
casting. The most striking feature is the low ductility of the 
metal. All of the specimens showed evidence of unsoundncss 
in their structure, tiny inclosed cavities, oxide inclusions, lack 
of intimate union, etc. Those features of unsoundncss are, 
seemingly, a necessary consequence of the method -of fusion 
as now practiced. They determine almost entirely the mechanical 
properties of the arc-fused metal. The observed elongation of 
the specimen under tension is due to the combined action of 

191 



192 ELECTRIC WELDING 

the numerous unsound spots rather than to the ductility of 
the metal. That the metal is inherently ductile, however, will 
be shown by the changes in the microstructure, produced by 
cold-bending. By taking extreme precautions during the 
fusion, a great deal of the unsoundness may be avoided and 
the mechanical properties of the metal be considerably im- 
proved. The specimens described, however, are more repre- 
sentative of actual present practice in welding. 

General Features of Microstructure. For purposes of com- 
parison the microstructure of the electrodes before fusion is 
shown in (1) and (2), Fig. 157. The "A" electrodes have 
the appearance of steel of a very low carbon content; in some 
cases they were in the cold-rolled state; all showed a consider- 
able number of inclusions. The "B" electrodes have the struc- 
ture of a mild steel and are much freer from inclusions than 
are those of the other type. It is, undoubtedly true, however, 
that the condition of the arc-fused metal with respect to the 
number of inclusions is a result of the fusion rather than of 
the initial state of the metal. 

It is to be expected that the microstructure of the material 
after fusion will be very considerably changed, since the metal 
is then essentially the same as a casting. It lias some features, 
however, which are not to be found in steel as ordinarily east. 
The general type of microstructure was found to vary in the 
different specimens and to range from a condition, which will 
be designated as "columnar" to that of a uniform fine equi- 
"axed crystalline arrangement as shown at 3 and 4, Fig. lf>7A. 
This observation held true for both types of electrodes, whether 
bare or covered. In the examination of cross-sections of the 
blocks of arc-fused metal, it was noticed that the equi-axecl 
type of structure is prevalent throughout the, interior of the 
piece and the columnar is to be found generally nearer the 
surface i.e., in the metal deposited last. It may be inferred 
from this that the metal of the layers which were deposited 
during the early part of the preparation of the specimen is 
refined considerably by the successive heatings to which it is 
subjected as additional layers of metal are deposited. The 
general type of structure of the tension bars cut from the 
blocks of arc .fused metal will vary considerably according 
to the amount of refining which has taken place as well as 



METALLOGRAPHY OF ARC-FUSED STEEL 



193 



the relative position of the tension specimen within the block. 
In addition it was noticed th$b V:t%,miuiHnar and coarse equi- 
axed crystalline condition appears to predominate with fusion 
at high-current densities. 




FIG. 157. (1) fi A 7 ' 'Electrode, 5 / 3 ,-m- Diameter. Annealed As Received. 
(2) "B" Electrode, 3 /V iu - Diameter. Cold-Drawn. 
Picric Acid Etching. 




FIG. 157A. (3) Columnar Structure of B 2 . X^6. Five Per Cent Picric 
Acid Etching. (4) Kqui-axcd Structure of AD a . X 200 - Two P er 
Cent Alcoholic HN0 3 Etching. 

Microscopic Evidence of Unsoundness. In all of the speci- 
mens of arc-fused metal examined microscopically there ap- 
pear to be numerous tiny globules of oxide as shown in Figs. 
158 to 160. A magnification of 500 diameters is usually neces- 
sary to show these inclusions. In general they appear to have 



194 



ELECTRIC WELDING 




METALLOGRAPHY OF ARC-FUSED STEEL 195 

no definite arrangement, but occur indiscriminately through- 
out the crystals of iron. 

A type of unsoundness frequently found is that shown in 
(5), (6) and (7), Fig. 158; this will be referred to as "metallic- 
globule inclusions." In general these globules possess a 
mierostructui'c similar to that of the surrounding metal, but 
are enveloped by a film, presumably of oxide. It seems prob- 
able that they- are small metallic particles which were formed 
as a sort of spray at the tip of the electrode and which were 
deposited on the solidified crust surrounding the pool of molten 
metal directly under the arc. These solidified particles ap- 
parently are not fused in with the metal which is subsequently 
deposited over them i.e., during the formation of this same 
layer and before any brushing of the surface occurs. By taking 
extreme precautions during the fusion, a great deal of this 
unsoundness may be avoided and the mechanical properties of 
the metal may be considerably improved. 

Characteristic " Needles" or "Plates." The most char- 
acteristic feature of the steel after fusion is the presence of 
numerous linos or needles within the crysals. The general 
appearance of this feature of the structure is shown in (8) 
to (11), Fig. 159, inclusive. The number and the distribution 
of these needles wore found to vary greatly in the different 
specimens. In general, they are most abundant in the columnar 
and in the coarse oqui-axed crystals; the finer equi-axed crystals 
in some specimens wore found to be quite free from them, 
although exceptions were found to this rule. In general, a 
needle lies entirely within the hounds of an individual crystal. 
^Some instance's were found, however, whore a needle appeared 
to lie across the boundary and so lie within two adjacent 
crystals. Several instances of this tendency have been noted 
in the literature on this subject. The needles have an ap- 
preciable width, and when the specimen is etched with 2 per 
cent alcoholic nitric acid they appear much the same as 
cementite i.e., they remain uncolorod, although they may 
appear to widen anil darken if the etching is prolonged con- 
siderably. The apparent widening is evidently due to the 
attack of the adjacent ferrite along the boundary line between 
the two. The tendency of the lines to darken when etched 
with a hot alkaline solution of sodium pierate, as reported 



196 



ELECTRIC WELDING 



y$$$*tf.y 

iff ^.i'4*: iJ; ''>': 




PIG. 159 (8 to 11). Characteristic "Needles" or "Plates" 

(8) BD etched with 5 per cent picric acid in alcohol. 

(9) Specimen BDs after using for thermal analysis, re-heated in vacuo to 900 
deg. C. four times. Picric acid etching. 

(10) Same as (9) except etched in hot alkaline sodium picrate solution. 

(11) Specimen of welded joint between slip-plate. Additional very small needles 
are noted. Etching: 2 per cent HNOs in alcohol. 



MKTALLOUHAPHY OF AIUM'TSKD 8TEKL 197 

by i'omstock, was confirmed; (]0i illustrates the appearance 
when etched ill this manner. The needles are sometimes found 
in a rectangular grouping - i.e., they form angles ol' 90 dcg. 
with one another. In other eases they appear to be arranged 
along the octahedral planes of the crystal i.e., at (10 deg. to 
one another. This is best seen in specimens which have been 
heated, as explained below: 

In some of the specimens certain crystals showed groups 
of very fine short needles as in (11), The needles comprising 
anv otic group or family are usually arranged parallel to one 
another, but the various groups are often arranged definitely 
with respect to one another in the same manner as described 
above, Similar needles have been reported in articles by 
S, W. Miller. 

An attempt was made by Dr. P. D. Meriea to determine' 
whether the so called Hues or needles were really of the shape* 
of needles or of tiny plates or scales. An area was carefully 
located tits a spet'iiueu prepared I'MT microscopic examination, 
\\lttch was then ground <louu slightly and repolished several 
times. Il was possible to measure the amount of metal removed 
during I lie slight ^rindiiHH by observing the gradual disap- 
pearance of crrtaiit of the spherical oxide inclusions the 
diameter ul * whii'h could be accurately measured. By slightly 
ctehiii'4 the specimen aft'-r polishiiig anew it was possible to 
follow the gradual disappearance of some of the most prominent 
tit'i'dh-s and to measure the masitattm **deptir* of HiH'h iii'cdles. 
ll \\as conchuleil fi'uin flu- series of examinations that the term 
*"jilat-" i"'* more curredly descriptive of this feature 1 of the 
structure tiiau "Hiu^ 1 r M !ie*'dle," The thickness of the plate 
t.r., tin* uidlli of tlie iienlle viirieH IVojii 0.0005 to 0,001 
lulu jiint the ttitlfli if tin plate (*'dcpth t% ) may he as great 
a. tMiui mill. Tin- ji r /i-Jmee of the platt*s after it rcgrinding 
ut th 'iHi'l'.tei ii'ieil for rut* roscopteal cxaittiuatiou may be nottni 
iij 'iuiiir !' III*- imentM,iph-* given by MillT. Tlie nut horn are 
itiil atvarr, itnve\i r, of any utlier attempt to determine the 
simp*' ii* thrsr pi. it*-* Iy actual iiteiisurementH of their 



Probiibly Due to Nitrate*.- The usual 

if th*- nahu 1 '- M*' H * ptif* -. IH that they arc due to the nitrogen 
hieh i-s taU-u up by th- Ir**n tluring its fusion. Other sug- 



198 ELECTRIC WELDING 

gestions which have been offered previously attribute them t< 
oxide of iron and to carbide. The suggestion concerning oxid< 
may be dismissed with a few words. The plates are distinctly 
different from oxide in their form and their behavior upoi 
heating. It is shown later that the tiny oxide globules coalesce 
into larger ones -upon prolonged heating in vacuo ; the plate: 
also increase in size and become much more distinct (see (32) 
(34) and (36), Fig. 166). In no case, however, was any inter 
mediate stage between the globular form and the plate pro 




FIG. 160. (12) Specimen AD 3 , Etched with 2 Per Cent Alcooholic Nitric 
Acid. Shows Pearlite Islands, ''Needles 7 ' and Oxide Inclusions 
X750. 

dueed such as would be expected if both were of the same 
chemical nature. 

Regarding the assumption that they are cementite plates, 
it may be said that the tendency during fusion is for the carbon 
to be "burned out," thus leaving an iron of low carbon content. 
In all the specimens, islands of pearlite (usually with cementite 
borders) are to be found and may easily be distinguished with 
certainty. The number of such islands in any specimen appears 
to be sufficient to account for the carbon content of the 
material as revealed by chemical analysis. In some cases the 
peariite islands are associated with a certain type of "lines" 



METALLOGRAPHY OF ARC-FUSED STEEL 



199 



or "needles" such as are shown in (12), Fig. 160. These 
needles, however, appear distinctly different from those of the 
prevailing type and are usually easily distinguished from them. 
The fact that the plates found. in the arc-fused metal are 
identical in appearance and in behavior (e.g., etching) as 
those found in iron which has been nitrogenized is strong 
evidence that both are of the same nature. (13) Fig. 161 
shows the appearance of the plates produced in electrolytic 
iron by heating it for some time in pure ammonia gas. These 
plates behave in the same characteristic manner when etched 
with hot sodium picrate as do those occurring in arc-fused 



^a>^Mpfe 

t^*Q.;f)W;i% 

'/mit 

WAi&:V 

[ .t:::-^^ l3 - 




14 



FIG. 1(51. (13) Characteristic Structure of Electrolytic Iron Heated in 

NH 3 at 650 Dog. 0. Two Types of Nitride Plates. Etched with 2 

Per Cent Alcoholic UNO,. X 37 ' r >- 
Fix;. 161. (14) Arc-Fused Iron. Produced in C0 2 Atmosphere. Type "A," 

Vsa-in. Electrodes, 150 Amperes. Etched with 5 Per Cent Picric Acid 

in Alcohol. X 375 - 

i ron i.e., they darken slightly and appear as finest rulings 
across the bright 1'crrite. The fact that the nitrogen content 
of the steel as shown, by chemical analysis is increased by the 
arc-fusion also supports the view that the change which occurs 
in the structure is due to the nitrogen. The statement has 
been made by Ruder that metal fused in the absence of nitrogen 
i.e., in an atmosphere of carbon dioxide or of hydrogen 
does not contain any plates and hence the view that the plates 
arc due to the nitrogen is very much strengthened. In (15), 
Fig. 162, the appearance of specimens prepared at the Bureau 
by arc fusion of electrodes of type "A" in an atmosphere of 



200 



ELECTRIC WELDING 




METALLOGRAPHY OF ARC-FUSED STEEL 201 

carbon dioxide is shown. The microscopic examination of the 
fused metal shows unmistakable evidence of the presence of 
some plates, although they differ somewhat from those found 
in nitrogenized iron and in metal fused in the air by the 
electric arc. Evidently they are due to a different cause from 
the majority of those formed in the iron fused in air. For 
convenience, in the remainder of the discussion the "plates" 
will be referred to as "nitride plates." 

Relation of Microstructure to the Path of Rupture. The 
faces of the fracture of several of the tension specimens after 
testing were heavily plated electrolytically with copper so as 
to preserve the edges of the specimens during the polishing 
of the section and examined microscopically to see if the course 
of the path of rupture had been influenced to an appreciable 
extent by the microstruetural features. In general, the frac- 
ture appears to be intererystalline in type. Along the path 
of rupture in all of the specimens were smooth-edged hollows, 
many of which had evidently been occupied by the "metallic, 
globules" referred to above, while others were gas-holes or 
pores. Portions of the fracture were intracrystalline and 
presented a jagged outline, but it cannot be stated with cer- 
tainty whether the needles have influenced the break at such 
points or not. (16) shows the appearance of some of the 
fractures and illustrates that, in general, the "nitride plates" 
do not appear to determine to any appreciable extent the course 
of the path of rupture. 

The behavior of the plates under deformation can best 
be seen in thin specimens of the metal which were bent through 
a considerable angle. Results of examination oi: welds treated 
in this manner have been described by Miller. Small rec- 
tangular plates of the are-fused metal, approximately Y. r2 in. 
thick, were polished and etched for microscopic examination 
and were then bent in the vise through an angle of 20 deg. 
(approximate). 

In (18) to (21), Fig. 163, inclusive are given micrographs 
illustrating the characteristic behavior of the material when 
subjected to bending. For moderate distortion the nitride 
plates influence the course of the slip-bands in much the same 
way that grain boundaries do- i.e., the slip-bands terminate 
usually on meeting one of the plates with a change of direction 



202 



ELECTRIC WELDING 



so that they form a sharper angle with the plate than, does 
the portion of the slip-band which is at some distance away 
(18). When the deformation is greater the slip-bands occur 
on both sides of the nitride plate, but usually show a slight 
variation in direction on the two sides of the nitride plate 
(19) ; this is often quite pronounced at the point where the 
plate is crossed by the slip-band. In a few cases evidence 




FIG. 163. (18 to 21) Behavior of "Nitride Plates" During Plastic Do- 
formation of the Iron. Specimen 1UX, Etched with 2 Per Cent. 
Alcoholic, Nitric Acid Before Bending, x ' r > 0() - 

of the "faulting" of the plate as a result of severe distortion 
was noted (20). This was a rare appearance, however, because 
of the nature of the metal, and is not shown in (21). On 
account of the inclusions and other features of unsoundness 
of the metal, rupture occurs at such points before the sound 
crystals have been sufficiently strained to show the character- 
istic behavior of the plates. Other micrographs show the 
beginning of a fracture around one of the "metallic globule " 



METALLOGRAPHY OF ARC-FUSED STEEL 203 

;lusioiis before the surrounding' metal has been very severely 
ained. For this reason the influence of the plates on the 
jchanical properties of the crystals cannot be stated with 
I'tainty. It would appear, however, that on account of the 
parently. unavoidable unsoundness of the metal, any possible 
luence of the nitride plates upon the mechanical properties 

the material is quite negligible. 

Some of the same specimens used for cold bending- were 
n partially in two after localizing the tear by means of a 
AT cut in the edge of the plate. The specimen was then 
pper plated and prepared for microscopic examination, the 
t'faee having been ground away sufficiently to reveal the 
.Id-metal with the tear in it, The nitride plates did. not 
pear to have determined to any extent the path taken in 
3 rupture produced in this manner. 

Effect of Heat Treatment Upon Structure. With the view 

possibly gaining- further information as to the nature of 
;i plates (assumed to be nitride), which constitute such a 
aracteristic feature of the microstructure, a series of heat 
Fitments were carried out upon several specimens of 
3-fused electrodes of both types. Briefly stated, the 
xatnient consisted in quenching the specimens in cold 
iter after heating 1 thorn for a period of ten or fifteen minutes 
a temperature considerable above that of the Ac a transforma- 
n; 925, 950 and 1,000 dog. 0. were the temperatures used, 
ter microscopical, examination of the different quenched 
?cirnons they were tempered at different temperatures which 
ried from. 600 to 925 cleg. C. for periods of ten and twenty 
nutes. The samples which were used were rather small in 
;e, being only ^ in. thick, in order that the effect of the 
, v atment should be very thorough, were taken from test bars 
, A;j, AI) 10 , !>.,, !> and B,,. These represented metal, which 
d been deposited under different conditions of current den- 
y, as shown in Table X. No plates were found to be present 

any of the specimens after quenching. (22) Fig. 164 shows 
e appearance of one of the quenched bars, a condition which 

typical of all. The structure indicates that the material 
mprising the plates had dissolved in the matrix of iron and 
d been retained in this condition upon quenching. The 
edlc-likc striatlons within the individual grains are char- 



204: 



ELECTRIC WELDING 




s 

PM 



S-H 



Pl <y 

CQ "o 
rT! 

3 

1 1 

o 

fc 



^ W 
O 

Pi " 

ll 

I 

2 02 



PH 
S 



."ti O CO 

g w ^ 

I X ^ 



rd <H 

O O 



D C? 



s* 



a, tup 
to a 

^ *a^ 



1 o 

i O 

> to 



6p 
XL 



| s 

O ^ T3 



i o 



oS 
CQ 



METALLOGRAPHY OF ARC-FUSED STEEL 205 

acteristic of the condition resulting from the severe quenching 
and are to be observed at times in steel of a very low carbon 
content. (23) shows the appearance of one of the "A'* elec- 
trodes (%2 hi.) quenched in cold water from 1,000 dcg. C. 
Some of the crystals of the quenched iron also show interior 
markings somewhat similar in appearance to the nitride plates 
(24). These are, however, probably of the same nature as 
the interior tree-like network sometimes seen in ferrite which 
has been heated to a high temperature. The striations were 
found to be most pronounced in the specimens of arc-fused 
metal which were quenched from the highest temperatures, 
as might be expected. Brauiie states that nitride of iron in 
quenched metal is retained in solution in the marteiisite. The 
same may be inferred from the statement by Giesen that "in. 
hardened steel, it (nitrogen) occurs in martensite. " Ruder 
has also shown that nitrogenizcd electrolytic iron (3 hr. at 700 
deg. C. in ammonia) after being quenched in water from tem- 
peratures 600 to 950 deg. C. shows none of the plates which 
were present before the specimen was heated. 

The sets of specimens (A,,, A , AD 10 , B 27 B ( . and B,,) 
quenched from above the temperature of the Ac a transforma- 
tion were heated to various temperatures, 600, 700, 800 and 
925 deg. C. In all cases the specimens were maintained at 
the maximum temperature for approximately ten to fifteen 
minutes and then cooled in the furnace. (25) to (30), Fig. 165, 
inclusive summarize the resulting effects upon the structure. 
Heating to 650 deg. C. is not sufficient to allow the plates 
to redevelop, but in the specimens heated to 700 deg. C. a few 
small ones were found. The effect is progressively more pro- 
nounced with the increased temperature of tempering, and in 
the material heated to 925 deg. C. they are as large and as 
numerous as in any of the arc-fused specimens. The heating 
also develops the islands of pearlite which are not always to 
be distinguished very clearly in the simple fused metal. The 
work of Ruder shows that nitrogenized iron which has been 
quenched and so rendered free from the nitride plates behaves 
in a similar manner upon heating to temperatures varying 
from 700 to 950 deg. C. ; the plates reappear after a heating 
for fifteen minutes at 700 deg. C. (or above), followed by a 
slow cooling. The similarity in behavior of the two is a 



206 



ELECTRIC WETTING 



PS 



^zpf^^l 

]'$'?}^j$ f ft|J'f 3^5^l^ 



* ? y< l ^i^i3^fi '^^V>x^'*' 1 ^^ t : : 



V^ji'^iE^SyV'^ 




JTiG. 165. (25 to 30) Effect of Heat-Treatment of Arc-Fused Iron. 
All etched with 2 per cent alcoholic HNOa. X 450. 

(25) Specimen AD 10 as deposited. 

(26) Same after quenching from above 1IC: and reheating to 650 deg. C. No 

1>la (27) Specimen 10 AD 10 after quenching from above HCa and reheating to 700 

deer C. "Plates beginning to reform. 

V^8} Specimen Bo after quenching from above AC;j and reheating to 800 deg. C. 

20 Specimen B 2 after quenching from above AOa and reheating to 925 deg. C. 

(30) Specimen As after quenching from above ACa and reheating to 925 deg. C. 



MKTALUHUUPIlY OF AlUM'TSED STEEL 



207 






';%- '\ \ A 

' ', / * - * <S 

';' ^^ / '^ ^ ' 4 '-> 

&'i "* t /<'",/' '">r 

'{$%*''* 4, * ^ *^ ' 




Fil. Kti;. (:tl tn n 



Kffivt of 0-hr. Hontintf at iu0 1H% C.I in Vac.uo. 

Hh ' J..T mil ntn.h.li.- 1 1 >i *>,. \ 450, 
:U i iKjimJ -sfrut inn- .f A!*;. 



rr f Aw. 



208 



ELECTRIC WELDING 



further line of evidence that the arc-fused metal contains more 
or less nitrog'cnized iron throughout its mass. 

Plates Eemain After Long Annealing. The persistence of 
the nitride plates was also studied in specimens heated at 
1,000 deg. 0. in vacuo for a period of 6 hr. A set of specimens 
(one each of test-bars AD 2 , A 3 , AD 6 , A 10 , B 2? B 4 , B- and BD 5 ) 
was packed in a Usalite crucible, and covered with alundum 
"sand" ; this crucible was surrounded by a protecting alundum 
tube and the whole heated in an Arsem furnace. A vacuum, 



'"" 




FIG. 167. (37) Effect of Pronounced Heating Upon the Structure of 

Arc-Ftised Iron. 

Specimen ADio was heated for 6 hr. in vacuo at 1000 deg. C. The micrograph 
represents a section of the specimen at one corner. The oxide and "nitride plates" 
have been removed in the exposed tip of the thread. Etching, 2 per cent alcoholic 
flotation of nitric acid. X 150. 

equivalent to 0.2 mm. mercury, was maintained for the greater 
part of the 6-hr, heating period; for the remainder of the 
time the vacuum, was equivalent to 0.1 to 0.2 mm. mercury. 
The specimens were allowed to cool in the furnace. Ruder 
has stated that 1 hr., heating in vacuo at 1,000 deg. 0. was 
sufficient to cause a marked diminution in the -number of plates 
in both are-word material and nitrogenized iron and that at 
1,200 deg. 0. thoy disappeared entirely. 

The results obtained are shown in (31) to (36), Fig. 166, 



METALLOGRAPHY OF ARC-FUSED STEEL 209 

iusivc. In contradistinction to Ruder 's work the plates are 
i-e conspicuous and larger than before, the oxide specks 
larger and fewer in number. Many of the "plates" appear 
have been influenced in their position by an oxide globule, 
would appear that the conditions of the experiment are 
orable for a migration of the oxide through an appreciable 
:ance and for a coalescing into larger masses. (32), (34) 
I (36) all show some cementite at the grain boundaries 
ich resulted from the "divorcing" of pearlite. The oxide 
sliminated entirely in a surface layer averaging approx- 
itely 0.15 mm. in depth. Only in projections (right-angled 
ncrs, sections of threads of the tension bar, etc.), was there 
r removal of the. nitride plates by the action of the continued 
,ting in vacuo. This is shown in (37), Fig. 167, which illus- 
tes the removal of the oxide inclusions also. No evidence 
3 found that the small amount of carbon present in the 
-fused metal is eliminated, particularly beneath the surface. 
(6) Fig. 158 illustrates an interesting exception to the rule 
,t the nitride plates are flat. In the metallic and globular 
lusion shown the plates have a very pronounced curve. The 
leral appearance suggests that the "metallic globules" solid- 
d under a condition of "constraint" and that this condi- 
n still persists even after the 6-hr, heating at 1,000 deg. C. 
ich the specimen received. 

Several of the specimens which were heated in vacuo (6 hr. 
1,000 cleg. C.) were analyzed for nitrogen. The results are 
rcn in Table XVI. 

TABLE XVI. CHANGE IN NITROGEN CONTENT UPON HEATING 



Wt. of 
Sample 
{Specimen in Gr. 
1.39 


Average Nitrogen Content, 
per Cent 
Before After Heating 
Heating in Vacuo. 
0.127 0.062 
0.124 0.078 
0.140 0.059 
0.121 0.054 


Loss 
per Cent 
51 
37 
57 
55 


6.0 


>, 1.62 


1.16 





The fact that the specimens lose nitrogen upon heating 
Ithough the amount remaining is still many times the 
trogen-content of the metal before fusion), coupled with 
e fact that the "nitride plates " are larger and more con- 



210 ELECTRIC WELDING 

spicuous after heating than before, suggests very strongly 
that these plates are not simple nitride of iron. The method 
used for the determination of nitrogen gives only the "nitride" 
nitrogen, hence a possible explanation for the change in 
nitrogen content is that it has been converted into another 
form than nitride and may not have been eliminated from 
the specimen. 

Thermal Analysis of Arc-Fused Steel. In order to throw 
further light oil the nature of the plates (nitride) found in 
the metal after fusion in the arc, the thermal characteristics 
of the electrode material before and after fusion as revealed 
by heating and cooling curves were determined. Samples of 
a 3 / 10 -in. electrode of type "A" and of the specimen. A, which 
resulted from the fusion were used as material (composition 
in Tables IX and XII.) 

TABLE XVII. THE THERMAL CHARACTERISTICS OF ARC-FUSED IRON 



















A 




A -~ 


^ 

li 

|So : 


Ao2, Maximum 
Deg. C. 

Beginning 


Maximum, Deg. C. f 

i 


c 


Maximum Temp., 
Deg. C. 


CJ> 

O 

o c 

I s 


M 

C 

c 

e 

1 


Maximum, Deg. C. ! 




Maximum, Deg. C. ^ 


Unfui-ed Electrode 





15* 


768 892 


910 


918 


960 




896 


893 


879 


766 






765 897 


911 


916 


960 




895 


891 


879 


766 


Arc-Fused 


Metal t 










0. 


14 


764 .... 


847 


874 


960 


28 


847 


838 


820 


764 





13 


764 


849 


876 


985 


42 


847 


836 


822 


764 


0. 


13 


764 . . 


844 


870 


960 


29 


847 


837 


821 


765 


0. 


13 


766 


850 


874 


1,035 


256 


848 


835 


816 


764 



* Heated at rate of 0. 16 dcg. C. per see., cooled 0. 15 deg. C. per sec. for other 
specimens, the rate of cooling equaled the rate of heating. 

t The same specimen was heated four times in succession, as shown. (Fig. 38) 



In Fig. 168 are given the curves obtained which show the 
characteristic behavior of the arc-fused metal upon heating. 
The commonly used inverse-rate method was employed in plot- 
ting the data; the details of manipulation and the precautions 
necessary for the thermal analysis have already been described. 
In Table XVII are summarized the data shown graphically in 
the last cut. 

The principal change to be noted which has resulted from 



METALLOGRAPHY OF ARC-FUSED STEEL 211 



5 - 

Q 
u 

Q.. 






t . 



en - 
.2- 



_j 

uJ ' 

5 

_i 



S2 
ct: 
o 



.... 



I s 



cu: 3 



212 ELECTRIC WELDING 

the arc-fusion of the iron is in the A 3 transformation. This 
is now very similar to the corresponding change, observed in 
a very mild steel (e.g., approximately 0.15 per cent carbon). 
That the difference in the A 3 transformation of the arc-fused 
metal as compared with that of the original electrode is not 
due to an increase in the carbon content is evident from the 
lack of the sharp inflection of the A^ transformation ("pearlite 
point") which would, of necessity, be found in a low carbon 
steel. No evidence of the A 1 change was observed for the 
arc-fused iron within the range of temperature, 150 to 950 
deg C. The change in the character of the A 3 transformation 
is without doubt to be attributed to the influence of the 
increased nitrogen-content of the iron. 

The specimen was maintained above the temperature of 
the A s transformation for a total period (four heatings) of 
6 hr., the maximum temperature being 1,035 deg. C. The 
transformation apparently is unaffected by the long-continued 
heating, thus confirming the results described in the preceding 
section. 

In discussing the properties of steel nitrogenized by melting 
it in nitrogen under pressure, Andrews states that it was 
found possible to extract almost entirely the small quantities 
of nitrogen by heating a specimen at 1,000 deg. C. in vacua 
for periods of 1 to 6 hr. The metal used contained 0.16 per 
cent carbon and 0.3 per cent nitrogen. Thermal curves are 
given to show that there arc no critical transformations in 
the material; the nitrogen suppresses them. They gradually 
reappear, however, as the nitrogen is removed by heatijig the 
material in vacuo at 1,000 deg. C. Several days 7 heating was 
required, however, to obtain an entirely degasified product, 
the carbon being removed also. A further statement is made 
that a steel of 0.6 per cent carbon content containing 0.25 per 
cent nitrogen can be brought back to the normal state of a 
pure steel only by several weeks' heating in vacuo. 

The results of the thermal analysis add considerable, con- 
firmatory evidence to support the view that the plates existing 
in the arc-fused metal are due to the nitrogen rather than 
to carbon. 

Summary. Microscopic examination of bent pieces of arc- 
fused metal show that the metallic grains are inherently ductile, 



METALLOGRAPHY OF ARC-FUSED STEEL 213 

en to a high degree. Grosser imperfections, however, are 
itirely sufficient to mask this excellence. 

The view that the characteristic features observed in the 
ructure of the arc-fused iron are due to the increased nitrogen 
intent is supported by several different lines of evidence, 
liese include the likeness of the structure of the material 

that of pure iron which has been "nitrogcnized," the 
milarity in the behavior of both arc-fused and nitrogenized 
on upon heating, the evidence shown by thermal analysis 
; the arc-fused metal, together with the fact that, as shown 
y chemical analysis, the nitrogen content increases during 
ision, while the other elements, aside from oxygen, decrease 
i amount. The characteristic form in which oxide occurs in 
on, together with its behavior upon heating, renders the 
ssumption that the oxide is responsible for the plates observed 
i the material a very improbable one. 

Judged from the results obtained, neither type of electrode 
ppears to have a marked advantage over the other. The use 
f a slight protective coating on the electrodes does not appear 
> affect the mechanical properties of the arc-fused metal 
uiterially in any way. The specimens were prepared in a 
umner quite different from that used ordinarily in electric-arc 
welding and the results do not justify any specific rccom- 
concerning methods of practice in welding. 



CHAPTER XI 
AUTOMATIC ARC WELDING 

The automatic are welding machine, made by the General 
Electric Co., Schenectady, N. Y., is a device for automatically 
feeding metallic electrode wire into the welding arc at the 
rate required to hold a constant arc length, says H. L. Unland 
in a paper read before the American Welding Society. Under 
these circumstances the electrical conditions are kept constant 
and the resulting weld is uniform and its quality is thereby 
improved. It is possible with this device to weld at a speed 
of from two to six times the rate attained by skilled operators 
welding by hand. This is partly due to the stability of the 
welding conditions and partly due to the fact that the elec- 
trode is fed from a continuous reel, thus eliminating the chang- 
ing of electrodes. The automatic welding machine is adaptable 
to practically any form of weld from butt welding of plates 
to the depositing of metal on worn surfaces such as shafts, 
wheels, etc. 

Everyone who has made any investigation of electric arc 
welding has noted the wide variation in results obtained by 
different welders operating, as nearly as can be determined, 
under identical conditions. This also applies to the operations 
of a single welder at different times under identical conditions. 
These variations affect practically all factors of welding such 
as speed of welding, amount of electrode consumed, etc. When 
indicating instruments are connected to an electric welding 
circuit, continual variations of considerable magnitude in the 
current and voltage of the arc are at once noticed. Consider- 
able variation was found some years ago in the cutting of 
steel plates by the gas process and when an equipment was 
devised to mechanically travel the cutting torch over the plate 
a series of tests, to determine the maximum economical speed, 
gas pressure, etc., for the various thickness of plate were made. 

214 



AUTOMATIC'. ARC WKLDING 215 

The result was thai the speed of cutting \va,s increased to as 
much as four or five times the rate possible when operating 
under the unsteady conditions ineideiit to hand manipulation 
of the torch. Further, the gas consumption lor a given cut 
was found to be decreased very greatly. 

As a result of many experiences an investigation was started 
to determine what could be done in controlling the Teed oil 
the electrode to the electric arc in a metallic electrode welding 
circuit. An electric arc is inherently unstable, the fluctuations 
taking place with extreme rapidity. In any regulating device, 
the sensitiveness depends on the percentage of variation from 
normal rather than on the actual magnitude of the values, since 
these are always reduced to approximately a common factor 
by the use of shunts, current transformers, or scries resist- 
ances. The characteristics of practically all electric welding 
circuits arc such that the current and voltage are inter-related, 
an increase in one causing a corresponding decrease in the 
other. Where this is I be case it will generally be found that, 
the percentage variation of the voltage from normal when 
taken at tin 4 customary arc voltage of 20, will be approximately 
twice the percentage variation in current. Further, an increase* 
in arc voltage, other conditions remaining the same, indicates 
that the arc has been lengthened, thus giving the metal a 
greater opportunity to oxidixc in the arc with a probability 
of reduction in quality of the weld. The automatic arc weld- 
ing machine utili/.cs tin* arc voltage as the basis for regulating 
the equipment. The rate of feeding the wire varies over* a wide 
range, due to the use of electrodes of different diameters, 
the use of different current values, etc., caused by details of the 
particular weld to he made. The simplest and most reliable 
method of electrically obtaining variations in speed is by 
means of a separately excited direct current motor. Thus the 
operation of this equipment is limited to direct current arc 
welding circuits, hut these may be of any established type, 
the variations in characteristics of the welding circuits being 
taken can* of by proper selection of resistors, coils, etc., in 
the control. 

The Welding Head, The welding head consists essentially 
of a set of rollers for gripping the wire and feeding it to 
the arc, These rollers are suitably connected through gearing 



516 ELECTRIC WELDING 

,o a small direct-current motor, the armature of which is coii- 
iccted across the terminals of the welding arc. This connec- 
tion causes the motor to increase in speed as the voltage across 
he arc increases due to an increase in the length of the arc 
ind to decrease in speed as the voltage decreases, due to a 
shortened arc. A small relay operating oil the principle of 
i generator voltage regulator is connected in the field circuit 
jf the motor which assists in the speed control of the motor 
as the arc voltage varies. Bheostats, for regulating- and adjust- 
ing the arc voltage, are provided by means of which the 
equipment can be made to maintain steadily an arc of the 
desired length and this value may be varied from over twenty 
to as low as nine volts. No provision is made in the machine 
for adjustment of the welding current since the automatic 
operation is in no way dependent on it. The welding current 
adjustment is taken care of by the control panel of the welding 
set. This may be either of the variable voltage or constant 
potential type but it is necessary to have a source of constant 
potential to excite the fields of feed motor. It may be possible 
to obtain this excitation from the welding circuit, but this 
is not essential. The voltage of both the welding and constant 
potential circuits is immaterial, provided it is not too high, 
but these voltages must be known before the proper rheostats 
can be supplied. 

On account of the great variation in conditions under which 
this welding equipment may be used it is provided with a 
base which may be bolted to any form of support. It may be 
held stationary and the work traveled past the arc or welding 
head may be movable and the work held stationary. These 
points will be dictated by the relative size of the work and 
the head and the equipment which may be available. Provision 
must be made for traveling one or the other at a uniform 
speed in order to carry the arc along the weld. In the case 
of straight seams a lathe or planer bed may be utilized for 
this purpose and for circular seams a lathe or boring mill 
may be used. In many cases it will be found desirable to 
use clamping jigs for securely holding the work in shape and 
also to facilitate placing in position and removing from the 
feeding mechanism. 

In Fig. 169, the welding head is shown mounted on a special 



AUTOMATIC ARC WKLDINCJ 



217 



;>viee tor making circular welds. The work table is driven 
irough a worm and worm gear by means of a separate motor. 




he welding; hciid may be* led along the arm by means of 
it* hniidwht't'l, and it may be tilted at an angle of 45 deg. 



218 ELECTRIC WELDING 

both at right angles to the line of weld and also parallel 
to the line of weld. Fig. 170 shows the building up of a shaft, 
the work being mounted on lathe centers and the welding 
head placed on a bracket clamped to saddle. 

Fig. 171 shows a simplified diagram of the control of the 
feed motor. In this cut A is the regulating rheostat in the 
motor field circuit controlled by the arc voltage regulator ff; 
B is the adjusting rheostat in the motor field circuit; F 




Fie. 170. Set-Up for Building up a Shaft. 

indicates the feed motor field winding; M the feed motor wind- 
ing; D is the resistance in the motor armature circuit to adjust 
the speed when starting the feed motor before the arc is struck. 
The open-circuit voltage of the welding circuit in ordinarily 
considerably higher than the are voltage. This resistance /) 
is short circuited by contactor X when the are in struck. The 
arc voltage regulator maintains constant are voltage by 
varying the motor field strength through resistor A. The 
regulator is adjusted to hold the desired voltage by the rheostat 



AUTOMATIC ARC WKLDING 



219 



, Permanent resistance K is in series will) the over-voltage 
lay //, to compensate for the voltage of the welding circuit, 
ver voltage relay // holds open the coil circuit of the regulator 

until the electrode makes contact in order to protect the 
>il from burning out. 

Observation of indicating meters on the control panel show 
lat the current and voltage are practically constant, but it 
lould be remembered that all indicating meters have a certain 
nount of damping which prevents observation oF the varia- 
ons which are extremely rapid or oF small magnitude. The. 
sultant value as read on the instrument is the average 1 value, 
scillographs taken with short ares show that notwithstanding 
ic fact that the indicating meters show a constant value, a 




of Control of Feed Motor. 



of rapid short cireuits is continually taking place, 
ppnrently due to particles oF the molten wire practically short- 
irc'tiiting the arc* in passing From the electrode to the work. 
'his is indicated by the Fact that the voltage curve* Fell to 
*ro each time, and accompanying each such fluctuation then 1 
as an increase in the cur-rent. It was Found thai with the 
uortcr are the frequency of occurrence oF these short -circuits 
'as considerably higher than was the rase when the are was 
iereaned iu length. To all appearances the arc* was absolutely 
leady and continuous and there was no indication either by 
bscrvation oF the arc HselF or oF the instruments thai these 
henowcita were occurring. 

Some Work Performed By the Machine. The principal 
eld for an automatic arc welding machine is where a consider- 



220 ELECTRIC WELDING 

able amount of welding is required, the operations being a 
continuous repetition of duplicate welds. Under these condi- 
tions one can economically provide jigs and fixtures for 
facilitating the handling of the work and the clamping. Thus 
can be reaped the benefit of the increased speed in the actual 
welding which would be lost if each individual piece had to 
be clamped and handled separately. 

Examples of different jobs done with this machine, using 
various feeding and holding methods, are shown in the accom- 
panying cuts. Fig. 172 is a worn pulley seat on an electric 
motor shaft built up and ready to be re-turned to size. 

It is possible to build up pulley and pinion seats, also worn 
bearings, without removing the armature or rotor from the 







FIG. 172. Worn Motor Shaft Built Up. 

shaft and in practically all cases without removing the wind- 
ings due to the concentration of the heat at the point of the 
weld. On shafts of this kind, 3 to 4 in. in diameter, the figures 
are: current 115 amp.; are voltage 14; electrode 3 / 32 in. in 
diameter ; travel, 6 in. per min. ; rate of deposit about 2.1 Ib. 
per hour. 

Similar work on a 14-in. shaft where the flywheel seat 
21 in. long was turned undersize, was as follows : metal about 
Vie in. deep was deposited over the undersize surface, using 
current, 190 amp.; arc voltage 18; electrode -J in. diameter; 
travel 4 in. per min.; rate of deposit, about 2 Ib. per hour; 
welding time, 16 hr. ; machining time, 4 hr. 

Fig. 173 shows worn and repaired crane wheel flanges. 
These are easily handled by mounting on a mandrel in a lathe, 



AUTOMATIC ARC WELDING 



221 



and placing the welding machine on a bracket bolted to the 
cross-slide or the saddle. On wheels of this type 22 in. in 
diameter, the time taken to weld by hand would be about 
12 hr. and by machine 2 hr. ; machining time 4 hr. ; approximate 
cost by hand welding $9 ; by machine $4. 





FlG. 173. Worn and Repaired Crane Wheels. 




FIG. 174. Welded Automobile Hub Stampings. 

Fig. 174 is an automobile wire wheel hub stamping, to 
which a dust cover was welded as shown. Joint was between 
metal Vie and Vie in - thick - Current 100 amp. ; arc voltage, 
14 ; travel 10 in. per min. ; electrode 3 / 32 in. diameter. 



222 



ELECTRIC WELDING 



Fig. 175, welded automobile rear-axle housing, 3 / 1G in. thick ; 
current 120 amp.; arc voltage 14; travel 6 in. per rain.; elec- 
trode diameter 3 / 32 in. 

Fig. 176, welded tank seam ; metal -J- in. thick ; current 140 
anip. ; are voltage 14; travel, 6 in. per min. ; time for welding 
ten tanks by hand, 4 lirs. 40 min. ; by machine, 2 hrs. 




FIG. 175. Welded Rear-Axle Housing. 

Tables XVIII and XIX give an idea of the speed of welding 
which may be expected, but it should be borne in mind that 
these figures are actual welding speeds. It is necessary to 
have the material properly clamped and supported and to have 
it travel past the arc at a uniform speed. In some cases the 




FlG. 176 Welded Straight Tank Seam. 

figures given have been exceeded and under certain special 
conditions it may be desirable to use lower values than those 
given. 

TABLE XVIII. SEAM WELDING 



Thickness in Inches 


Amperes 


Speed, Inches Per Minute 




0.040 


45 to 50 


20 to 30 




1/16 


50 to SO 


35 to 25 




1/8 


80 to 120 


6 to 12 




3/16 


100 to 150 


4 to 6 



AUTOMATIC ARC WELDING 223 

TABLE XIX BUILDING UP (WHEELS oit SHAFTS) 



Diameter or 


Electrodes, Speed, In. per 


Lb. Deposit 


Thick., In. 


Dia., In. Amperes 


Min. 


Per Hour 


Up to 1" 


Vir, 60 to 90 


11 to 13 


1.04-1.5G 


Up to 3" 


Vas SO to 120 


6 to 8 


1.59-2.1 


Over 3" 


Y S 120 to 200 


4 to I) 


2.5 -4.5 



A SEMI-AUTOMATIC ARC-WELDING MACHINE 

A paper on "Welding Mild Steel," by H. W. Hobart, was 
read at the New York meeting of the American Institute of 
Mining and Metallurgical Engineers in 1919. In discussing 
this paper Harry D. Morton, of the Automatic Arc Welding- 
Co., Detroit, brought out some interesting things relating to 
Automatic Arc Welding: 

"The generally accepted theory of the electric are is that part of the 
electrode material is vaporized, and that this vaporous tube or column 
forms a path for the electric current. As a result of the vaporous 
character of the current path, all arcs are inherently unstable; and the 
maximum of instability is no doubt found in that form of arc employed 
for metallic-electrode welding purposes. We here have, in conjunction with 
the natural instability characteristic of all arcs rapidly fusing electrode 
materials and the disturbing effect of the constant passage through the 
are. of a large quantity of molten metal to form the weld. This molten 
metal must pass through the arc so rapidly that it will not be injured 
or materially contaminated; otherwise the weld will be useless. Prima 
facie, the combination of these unfavorable conditions would seem to 
justify fully the skepticism of most electrical engineers as to the possibility 
of affecting such control of the metallic arc as to permit of uniformity 
and continuity in welding results. In addition, there is another and more 
important factor, and one that seriously mitigates against this desired 
uniformity and continuity; namely, the personal equation of the operator. 
The consensus of opinion, so far as is known to the writer, seems to be 
that about 95 per cent, of the welding result is dependent on the skill 
of the operator and that at least six months 7 practice is necessary to 
acquire reasonably satisfactory proficiency. 

"As the result of thousands of observations of welds produced auto- 
matically (wherein the personal equation is entirely eliminated), the writer 
inclines toward the theory that the molten electrode material passes through 
the- arc in the form of globules; and that where J-in. electrode material 
is employed with a current of about 150 amp. these globules are deposited 
at the rate of approximately two per second. The passage through the 
are of each globule apparently constitutes a specific cause of instability 
in addition to those existent with slowly consumed electrodes. This 
hypothesis seems to be borne out by ammeter records, typical specimens 
of which appear in. Fig. 177, together with the fact that the electrode 



224 



ELECTRIC WELDING 



fuses at the rate of about 0.20 in. per see. Moreover, the globules appear 
to be approximately equal in volume to a piece of wire 0.125 in. in 
diameter and 0.10 in. long. 

"Assuming this theory to be correct, to maintain a uniform arc length 
in manual welding, the operator must feed the electrode toward the work 




FIG. 177. Typical Ammeter Charts of Operation of Morton Automatic, 
Metallic-Electrode Arc- Welding Machine. 

Average Time about 1 Min. 45 Sec. 

at the rate of 0,10 in. upon the deposition of each globule; in other words, 
0.10 in. twice per second, a synchronism beyond human attainment. 
Simultaneously with such feeding, the arc must be moved over the work 
to melt the work material, distribute the molten electrode material, and 
form the weld. Inasmuch as the effect of the arc is highly localized, 



AUTOMATIC ARC WELDING 225 

it is reasonable to suppose that different parts of the welding area present 
relatively wide variations in respect to temperature, fluidity, and conduc- 
tivity of the molten mass controlling factors not within the ken of the 
human mind. The situation is further complicated by the facts that 
neither the welding wire nor the work material is uniform in fusibility 
or in conductivity, and that the contour of the work varies continually 
as its surface is fused and the molten metal is caused to flow. The belief 
is general that a very short arc is productive of the best welding results; 
but it is an arc of this character that makes the greatest demands on 
the skill of the operator, for there is always the danger that the electrode 
will actually contact with the work and destroy the are. 

"As the fusing energy of the arc varies widely with fluctuations in 
the are length and as the uniformity of the weld depends on the constancy 
and correctness of this fusing energy, it seems remarkable that operators 
are able ever to acquire such a degree of skill as to enable them to produce 
welds that are even commercially satisfactory. Further, so far as the 
writer is informed, there is no means, other than such as would be 
destructive, for determining whether a completed weld is good or bad. 
The logical solution appeared to be the elimination of the personal equation 
and the substitution therefor of means whereby tendencies toward variations 
in the arc would be caused automatically to correct themselves, just as 
a steam engine, through the action of its governor, is caused to control 
its own speed. 

Methods of Mechanically Stabilizing and Controlling the Arc. Our 
efforts for a number of years have been directed toward stabilizing and 
controlling the metallic arc, and applying such stabilizing and controlling 
means to two general lines of welding machinery: (1) Machines for 
automatically feeding the electrode wire, with reference to the work, and 
producing simultaneously therewith relative movement between the wire 
and the work, and (2) what, for lack of a better term, might be called 
a semi-automatic machine, in which the feeding of the electrode and the 
control of the arc are accomplished automatically but the traversing of 
the electrode with reference to the work is manually effected by the operator, 
permitting him the exercise of judgment with reference to the quantity 
of metal to be deposited in various parts of the groove. The automatic 
machine has been in successful operation for a long period and the semi- 
automatic machine for about five months. While the goal was not attained 
without many difficulties and a great expenditure of time and money, the 
results have been surprisingly successful. 

* ' Because of the lack of any definite data as to what actually occurs 
in this form of arc, or why it occurs, due, no doubt, to the impossibility 
of differentiating between phenomena that are characteristic of the are 
and phenomena due to the personal equation of the welder, it seemed 
logical that the initial step should be to so environ the arc that it would 
not be subject to erratic extraneous influences, to the end that reasonably 
definite determinations might be substituted for scientific speculation. In 
the design and construction of the machines, great care was exercised 
to minimize the possibility of mechanical defects that might lead to 



226 ELECTRIC WELDING 

erroneous conclusions. Starting with the assumption that the work could 
only "be based on open-minded observation of the behavior of the arc 
under machine control, an automatic welding machine was built in which 
was incorporated the greatest possible number of adjustable features, in 
order that, if necessary, it might be possible to wander far afield in the 
investigations. This adjustability has proved invaluable in that it has 
permitted logical, consistent, and sequential experimenting over a very 
wide range of conditions. Working under these favorable circumstances, 
there were soon segregated a few clearly demonstrable facts to serve as 
a foundation for the structure, which has since been added to, brick by brick, 
as it were. 

"Efforts have been directed toward the practical rather than the 
scientific aspect of the subject. The operation of the automatic machines 
has brought to light many curious and interesting phenomena, some of 
which appear to negative conclusions heretofore formed which have been 
predicated upon observations made in connection with manual welding. 
It is hoped that these and other phenomena, which can thus be identified 
as purely arc characteristics, will be the subject of profitable scientific 
investigation when time is available for this purpose. 

"In the five forms of machines made in the course of the development, 
the welding wire is automatically fed to the arc; and, in the first four 
machines, the relative movement between the work and the welding wire 
is automatically and simultaneously effected. Early in his investigations, 
the writer concluded that a substantial equilibrium must be maintained 
between the fusing energy of the arc and the feeding rate of the welding 
strip; and it soon became evident that if the welding strip is mechanically 
fed forward at a uniform rate equal to the average rate of consumption 
with the selected arc energy, this equilibrium is actually maintained by 
the arc itself, which seems to have, within certain circumscribed limits, 
a compensatory action as follows: When the arc shortens, the resistance 
decreases and the current rises. This rise in current causes the welding 
strip to fuse more rapidly than it is fed, thereby causing the arc to lengthen. 
Conversely, when the arc lengthens, the resistance increases, the current 
falls, the welding strip is fused more slowly than it is fed, and the moving 
strip restores the arc to its normal length. 

"While this compensatory action of the are will maintain the necessary 
equilibrium between the fusing energy and the feeding rate under very 
carefully adjusted conditions, this takes place only within relatively narrow 
limits. It was very apparent- that, due to variations in the contour of 
the work, and, perhaps, to differences in the fusibility or conductivity of 
the welding strip or of the work, the range of this self -compensatory action 
of the arc was frequently insufficient to prevent cither contacting of the 
welding strip with the work or a rupture of the arc due to its becoming 
too long. The problem that arose was to devise means whereby the natural 
self-compensatory action of the are could be so greatly accentuated as to 
preclude, within wide limits, the occurrence of marked arc*, abnormalities. 
There was ultimately evolved, by experiment, such a relation between the 
fusing energy of the arc and the feeding rate of the welding strip as to 



AUTOMATIC ARC WELDING 



227 



give flu* desired atv length under nornuil conditions; and tendencies toward 
abnormalities in arc condition*, no matter how produced, were caused to 




ITS.- Piloted Cup Automat it-ally Welded by Metallic Kleetrode Are, 
I'rocess to Tube tn Form 7."-MM. Shrapnel Shell. 

imlyHh of K!wtr<ttl<* Mnt*rin!: Silicon, tJ.nu IVr (Vut; Sulphur, 0.01 a Vr (Vnt; 
iliurttH, {t.07 I*rr ('ml; Mntit;uuoM\ Tnu'c ; 1'urbtiu, O.U7 l*or CVat; Aluniiniuu, 
iVr LVnt, 




Kui. 17!*,- -Pilotrd (*up AittoHmtifally Wehlod by MetaU'u-KIctro(lo Arc 

JriM-i'.*H to Tube to Konn 7H-MM. Shrapnel Shell. 

Anl>ih tf KhTinitti' Mufrrittt: Silimn, (,: PIT (Vnt; Sulphur, 0.049 Por CVnt; 
!Mii'iit)urun 4 IU.H F*r (Vni ; MttiiKnt"j O.:u IVr <Vnt; <'nrh(, 0/2H P*r Out. 

briti^j iijft* ujTufiin MinpritMutiry means for automatically, projt(r k HHvely, 
unit i'orrrrtivi'Jy \iii'yni* this rclutioti !nt\vt*en fusing energy and feeding 



228 ELECTRIC WELDING 

rate, such compensatory means being under the control of a dominant 
characteristic of the arc. In their ultimate forms, the devices for effecting 
the control of the arc are simple and entirely positive in action, making 
discrepancies between fusing energy and feeding rate self -compensatory 
throughout widely varying welding conditions. For instance, the shrapnel 
shell shown in Fig. 178 was automatically welded with wire differing 
greatly in chemical constitution from that used on the shell shown in 
Fig. 179 (see analyses), yet no change was made in either the mechanical 
or the electrical adjustments. The radically different welding conditions 
were compensated for solely by the operation of the automatic control. 
The electrode materials used for the shells shown in Figs. 180 and 181 




Fro. 180. Piloted Cup Automatically Welded by Metallic-Electrode Arc 
Process to Tube to Form 75-MM. Shrapnel Shell. 

Analysis of Electrode Material: Silicon, 0.02 Per Cent; Sulphur, 0.032 Per Cent; 
Phosphorus, 0.008 Per Cent; Manganese, 0.20 Per Cent; Carbon, 0.18 Per Cent. 

differed so greatly from those employed respectively in welding the shells 
shown in Figs. 178 and 179 that a change in the relation between fusing 
energy and feeding rate had to be made manually. After this adjustment 
was made, the shells were welded with their respective electrodes, which varied 
widely in their chemical constitution, without further manually changing 
either the mechanical or the electrical conditions. 

"In a recent test of the semi-automatic machine, shown in Fig. 182, 
successful welds were made under the condition that the impressed voltage 
of the welding generator was changed throughout a range of from 50 to 65 
volts, without necessitating any manual adjustment. The only observable 
effects of the wide variations in the supply voltage were slight differences 
in the arc length. In short, the compensatory action of the control has 
proved effective over a wide range of welding conditions, not only as to 



AUTOMATIC ARC WELDING 



229 



the electrical supply and chemical constitution of both electrode and work 
materials, but also as to extensive variations in the contour of the work 
and in many other particulars. This makes it seem apparent that the 
machines do not represent merely successful laboratory experiments but 
are suited to the requirements of actual commercial welding. 

"One particularly interesting observation resulting from the experiments 
is that the angle of inclination of the electrode with reference to the work 
is very important. An angular variation of 5 deg. will sometimes determine 
the difference between success and failure in a weld. About 15 deg. from 
the perpendicular works well in many cases. In welding some materials, 
the electrode should drag, that is, point toward the part already welded 
rather than toward the un welded part of the seam. 




FIG. 181. Piloted Cup Automatically Welded by Metallic-Electrode Arc 
Process lo Tube to Form 7fi-MM. Shrapnel Shell. 

Analysis of Electrode Material: Silicon, 0.04 Per Cent; Sulphur, 0.016 Per Cent; 
Phosphorus, 0.05H Per Cent- Manganese, None; Carbon, 0.24 Per Cent. 

1 i While it has been customary in some welding systems to provide 
means whereby extra resistance is inserted in series with the arc at the 
instant of the initial contact which starts the flow of current, the resistance 
being automatically cut out upon the striking of the arc, experience with 
the automatic machines indicates that this is quite unnecessary. 

" Early in the experiments, it was noted that in many cases there was 
a decidedly marked affinity between particular electrode materials and 
particular work materials. A slight change in either element affects the 
degree of this affinity. While it has invariably been possible to contiol 
and maintain the arc and weld continuously, in some instances incom- 
patibility between electrode material and work material has been productive 
of interesting phenomena. For instance, the combination of work material 
(steel of about 0.45 per cent, carbon content) and the particular electrode 



230 ELECTRIC WELDING 

material used in Fig. 178 produced an are that was remarkably quiet and 
free from sputtering. Throughout the weld, this arc was suggestive of 
the quiet flame of a candle or lamp, the erratic behavior that we are 
accustomed to associate with the ordinary metallic arc being absent. The 
effect is reflected in the uniform deposition of the welding material. 

* ' On some classes of work material Bessemer wire, which some authorities 
claim cannot be used in metallic- electrode arc welding, produces an are 




FIG. 182. Morton Semi-Aiitomatic Metallic-Electrode Arc-Welding Machine. 

The Electrode is automatically fed to the arc, which is automatically maintained 
while the machine is manually moved along the groove to be welded. 

and a weld very satisfactory in appearance. On other work material, the 
Bessemer wire arc is violently explosive. These explosions are accompanied 
by quite sharp reports and the scattering over some considerable distance 
of globules of molten metal frequently 3 /32 in. or more in diameter. Under 
certain other conditions, apparently growing out of incompatibility between 
the work material and the electrode material, the oxygen flame accompany- 
ing the arc gyrates very rapidly about the arc, producing an effect sug- 
gestive of the 'whirling dervish/ 



AUTOMATIC ARC WELDING 231 

"From both the practical and the scientific points of view, the writer 
has experimented quite extensively with varying combinations of work 
material and electrode material. Throughout all the differences in arc 
conditions, many of which palpably accentuate the natural inclination 
toward instability, the control has so operated as to justify the expression 
'the arc persists.' 

"Generally speaking, the Swedish and Norway iron, wires seem to 
produce more quiet ares and, possibly, a more uniform deposition of electrode 
material, than do wires of other classes. These welds may perhaps be 
found to be slightly more ductile than those made with wires of other 
chemical composition. On the other hand, these soft wires, although un- 
doubtedly of relatively high fusibility, do not, for some reason, seem to 
produce an arc that cuts into some work material as deeply as might, be 
desired, nor as deeply as do the arcs formed with certain other kinds of 
wire. Considered from every angle, the writer is disposed to regard the 
Roebling welding wire as the best he has thus far tested for use on mild 
steel. The wire produces a reasonably quiet arc which seems to cut into 
the work to more than the ordinary depth, while, at the same time, the 
electrode material is fused with more than average rapidity thus increas- 
ing the welding rate. 

* * While scientists will no doubt ultimately arrive at the correct hypothesis 
for solving the problem of why one combination of electrode material and 
work material is productive of better results than can be obtained with 
another combination, the writer's conclusion is that, with the data at 
present available, the determinations must be made by actual experimenting 
having in mind the qualities desired in the particular weld, such as 
ductility, tensile strength, elongation, and clastic limit. Inasmuch as it 
is possible, with the automatic machine, to maintain arc uniformity with 
practically any kind of electrode material and to produce welds which, 
under low magnification, at least, appear to be perfect, and which respond 
favorably to ordinary tests such as bending, cutting and filing, it is reason- 
able to conclude that proper selection of electrode material will be productive 
of perfect welds on any kind of work material. To date, no steel has been 
tested on which apparently satisfactory welds could not be made. High- 
speed tungsten steel has been successfully welded to cold-rolled shafting, 
using Bessemer wire as electrode material, as is shown in Fig 18.J. 
Ordinary steels varying in carbon content from perhaps 0.10 to 0.55 per 
cent, have been welded with entire success. 

"Because of the fact that the complete welding operation has been 
automatic and may be continued for a considerable length of time, say 
5 min., an exceptional opportunity has been afforded for close concentration 
upon the study of the appearance of the arc. What seems to occur is 
that the molten metal in the crater is in a state of violent surging, sug- 
gestive of a small lake lashed by a terrific storm. The waves are clashed 
against the sides of the crater, where the molten metal of which they 
are composed quickly solidifies. The surgings do not seem to synchronize 
with nor to be caused by the falling of the globules of molten metal into 
the crater, but seem rather to be continuous. They give the impression 



232 



ELECTRIC WELDING 



that the molten metal is subjected to an action arising from the disturbance 
of some powerful force associated with the arc such, for instance, as 
might result from the violent distortion of a strong magnetic field. Alto- 
gether, the crater phenomena are very impressive,- and the writer hopes 
ere long to be able to have motion pictures made which, when enlarged, 
should not only afford material for most fascinating study, but also throw 
light upon some of the mysterious happenings in the are. 

So far, eleetrode wires J in. in diameter have been chiefly used in 
the machines. Successful welds have been made with current values ranging 
from below 90 to above 200 amp., at impressed voltages of 40, 45, 50, 




PIG. 183. Tungsten High-Speed Bing Automatically Welded by Metallic- 
Electrode to Cold-Kolled Core to Form Milling-Cutter Blank. 

55, 60, 65 and 80. Under these varying conditions, the voltage across 
the arc has been roughly from 16 to 22. The machines have thus far been 
run only on direct current. Inasmuch as it is possible, by electrical and 
mechanical adjustments, to establish nearly any arc length that may be 
found to be most desirable for a particular class of work, and as the 
control system will maintain substantially that arc length indefinitely, the 
fully automatic type of machine is nearly as certain in operation as a lathe, 
drilling machine, or any other machine tool. 

' ' The tool shown in Fig. 182 weighs about 10| Ib. The operator draws 
the tool along the groove to be welded at such a rate as will result in 
the deposition of the quantity of metal required to satisfactorily effect the 
weld. This tool is intended for use in the many restricted spaces en- 



AUTOMATIC ARC WELDING 233 

countered in ship welding, which would be relatively inaccessible to a fully 
automatic machine. In its use, the skill required by the operator is reduced 
to a minimum. After one man had practised with the welding tool for 
not more than 2 hr., the opinion was expressed that it would require six 
months to train a welder to such a degree of proficiency as to enable him 
to make a weld equally good in appearance. 

"Mr. Hobart, says 'There is always a matter of a 0.10 in. or more 
between the end of the welding rod and the work.' While undoubtedly 
it is difficult, if not impossible, to maintain in manual welding an 'arc 
shorter than this, the writer has frequently, with the automatic machines, 
made continuous and strikingly good welds with arcs of much less length. 
In fact, in some cases there has been continuously maintained an are so 
short that there hardly seemed to be any actual separation. The writer 




Fro. 184. No. 11 Gage Steel Tubing Automatically Welded by Metallic- 
Electrode Are Process at the Rate of One Foot per Minute. 

has even wondered whether, under these conditions, there was not a close 
approach to casting with a continuous stream of fluid metal acting as lhe 
current conveyor in lieu of or in parallel with the usually assumed vapor 
path. The work that has been done indicates that under automatic control 
much shorter arcs can be utilized than have hitherto been deemed possible, 
and with probable marked gain in quality of work in some instances also, 
that there is much to be learned as to the mode of current action and 
current conduction in such an arc. 

"With the automatic machine, black drawing steel 0.109 in. thick 
has been welded at the rate of 22 in. per minute. A Detroit manufacturer 
welded manually with oxy-acetylene at the rate of four per hour a large 
number of mine floats 10 in. in diameter, made of this material. The 
automatic machine made the welds at the rate of forty per hour. Liberty 



234 



ELECTRIC WELDING 



motor valve cages 2% in. in diameter have been welded to cylinders in 
36 sec., as against about 5 min. required for manual welding. No. 11 
gage steel tubing, shown in Fig. 184, has been welded, with an unnecessarily 




FIG. 185. Two J-in. Ship Plates Automatically Welded by Metallic- 
Electrode Are Process to Form Lap Joint. 




Fl<*. 186. Two -in. Ship Plates Automatically Welded by Metallic- 
Electrode Process to Form Butt Joint. 

heavy deposit of metal, at the rate of 1 ft. per minute. The productive 
capacity of the machines so far made has been from three to ten times 
that of manual welding methods, depending on the thickness of the work 



AUTOMATIC ARC WELDING 



235 



material; the difference in favor of automatic welding varies inversely 
as such thickness. The writer is now designing an improved type of 
machine for use especially on heavy work, with which machine it is expected 
to be able automatically to lap weld Hn. ship plates, in the manner shown 
in Fig. 185, at the rate of 15 ft. per hour. One of the largest shipbuilding 
concerns in the United States reports that the general average of all its 
manual welders on this class of work is from 1 ft. to 18 in. per hour. 
Other specimens of automatic welding on ship plates are shown in Figs. 
186 and 187. 

"Bare wire only has been used in the automatic machines; and the 
results obtained seem to indicate that the covering of the electrodes is an 
expensive superfluity. If the chief advantage of the covered electrode lies 
in the ability of the operator to maintain a very short are, an arc equally 
short and possibly shorter can be continuously maintained by the automatic 
machine using bare electrodes. 

4 ' No attempt has thus far been made to use the automatic machines 




FIG. 187. Two ^-in. Ship Plates Automatically Welded by Metallic-Elec- 
trode Arc Process, Showing First of Three Layers to Form Lap Joint. 

on overhead work. The welds made with the fully automatic machine have 
been of three kinds, the usual longitudinal form, annular about a horizontal 
axis, and annular about a vertical axis. 

"As far as the maintenance of arc uniformity and the apparent 
character of the welds arc concerned, the writer has repeatedly welded 
with wire showing evidence of pipes and seams, as well as with rusty 
wire and with wire covered with dirt and grease. In this connection it 
may be said that no pains is ever taken to remove rust, scale, or slag 
from the work material even where welds are superimposed, Apparently 
under uniform conditions of work traverse, arc length, and electrode angle 
of inclination, such as are possible in the automatic machine, impurities 
vanish before the portion of the work on which they occur reaches the 
welding area of the arc. 

"The writer is fully convinced that with the use of the automatic 
machine, ductility, like other physical properties in the weld, can be con- 
trolled "by proper selection of electrode wire, in conjunction with electrical 



236 



ELECTRIC WELDING 




Af'THM \Tir ARC \YKU>IN<; 



237 



and mechanical adjustments best suited to the particular purpose in view. 
Automata- weld- ha\e repeatedly been made on s /> ' IU - lu<1 ^ ^teel which, 
when subjected to a '."i de;,.;'. bend, showed a marked extrusion of tho 
welded material l<ul no sjj.ii of fracture. When the welded pieces are 
cut uith a haeks;i\\ t it is \TY unusual to he aide to not* 1 any diilerence 
in cutting qualities between the unueldeii and the welded parts. 

* * While the- automatic ma'hine has not leen used on metal less than 
d.inil tit. thick, if is fair to piesume that, with proper luljustments, entirely 
>atisfa'tory re>!i!f'-. can lie uliiaincd <n much thinner work 'particularly 
if {he nature uf the \uik is v -nch as to permit of the use of a chill. The 
lu'st nielhod in weldui|,*, \ery ll^jit metal seems to he to use a, small elect rode, 
a relatneh !v i-urrent, and a hi^h rate of work traverse. In this way 
welduii* CfilidtS loll'- muv he cont rolled in almost anv d<*s:red extent, hiea.UH(^ 



U 




the lii*iifi!i|. ! ; it'fi"ii of fhr tire CHI* I"' modified, itn efTivt iiileiitiely 
Itll'l file rdg"* ! l*e \\vMrii inihjrcfrd fit file I"u?-nfi^ urttou for UH hr*f 
u tiwr ii ? s in-gilt IM' f!ini n'"'iary t< jre\rtit hiiriiisi;* of lite inetnl, 
Tli"ii* 'oiil!tMfiT, tt'h-h -IITW t ! nnjuimtr ut *rd* 8 |- to ^liccr-u^fitllv wi'ld 
VIMA thw iiatft'iiiil, i'iiiiiiMf !u- liirS J\ the liiliiitili! welder, It IM here I hit! 
liir tt'fie$'iicr-t tliodrnf !> flit- pi'imittlil 'jimti become HWHt Uppltrefil, 
A ^'tv '4nkl \2tuutin MI iit' Iri4^th or thr leu**! lt--uf itijcy in moving the 

Uic \ri' lli' ttiU lull ililliM-i! rrtlliilllv i'i".ntitl Hi it*i hesttg littrisi'd through. 
In nlinti, Ihi-i -luvt t*!' tti'lfliitg rulln for ii ritriiitia!loif of fitcuttit4 nnd u 
ili*l'-i'> *s! fti!UD)>uttion l**i"ii"i Ilir rn|*iif*i|sfjeM of th* * hkillful limnuut 
drfSir ttr!X'l. Tlir? r fiM th^ tti*lK in UHUtlllv t!*m With tl' iXV licet \ !ei!<* 
lliittii', tthiM i-iu fining t-MudifiouM us*' fur tuoir eiiwily coil! rutted thuu in 
jMi^iiitilr $ UiiUiUjt) inftull'.*' i-h-rM^df arc WrMmtf, " 

SHEET METAL AKC-WKLDING MACHINE 

The* miiHitnr nhowtt In Pitf. 1HS is unrd by tlie 0(norl 
KJi'rtrif Co., SehfinTtJKly. N* Y., for iiri'-wt'lding <*rruKt<l 
\virK. Tli' sraiim niv 1 U5 in. I*'riic un<l tin 1 an* 



238 ELECTRIC WELDING 

is applied by means of a tapered carbon pencil 6 in. long, -| 
in. in diameter at the large end and -J- in. at the arc end. This 
concentrates heat where wanted. No metal is supplied to the 
weld, as the arc is employed simply to fuse the upturned edges 
as shown in Fig. 189. The metal welded is 1 / 16 and 3 / 32 in. 
thick. ' 

The speed on 1 / le -in stock is 5 1 / 2 in. per minute with a 
d.c. current of 45 amp., and 75 volts. On V 32 -in. stock the 
speed is the same but 70 amp. and 75 volts d.c. current is 
used. 



niAPTKR xi r 

BUTT-WELDINO MACHINES AND WORK 

Aside from are-w'ldintf machines, which have already been 
described, rleetrie w**ldintf machines may he all included under 
tiur head Itrsistanee Welding Machines. These may he 
divided tutu hull , spot-, seam-, mash- and, percussive-welding 
clasHex The first three are sometimes* for manufacturing pur- 
poses, used iti combinations in th sam* machine, sueh as a 
spot-awl'vaiu machine or a hutt and spot welding machine, 
niid so oft, This do" uuf mean that Ilie^e iliffereni mefhuds 
of welfiin*! art* Carried on at the same time, hut that a welder 
can dt isorK n l!* f ame laui'liiite hy hhuply Nliiffiiiic flie wtirk, 
itr a jtart nf lit* II \ture, 

In hutt \\ehlin?,?, att*''natinj.<: current, sinul** jhas** of any 
fMitmaereiif! frrt|Uf ue\ ?ueh is*-* UlJo, 4 M* or .Vtt \*lts f GO tyeleH, 
in i**ijiii!ioiiiy u>*ed IOUIT \olta5,*"^ und louer fr^qtietieieH can 
he lined, iiiif they a*ld In the ei>it of the machine, The machine 
can he u\^d im me pha.M*' f n tu*"j>hasc or a three-phase 
system, hut eaiui**t hi- ettiuteeted to KHM'e than one phast 1 of 
a thrn'-plw.e eireuit, Direct ctirreitt IN not iw*d becaus< there 



uitce, tt'iiieli iimli"^ lli" pourr, A?i nit e.\autple v 14 d,e, 
tiyiiiiiiitt will MI^" ,*ppr\5twiti'ly '* vll,** which will do for 
certain Liiid?* <*f uihiitu.?. Itut for tighter work* less current is 
lieinli'tt If resi^taoef $ n",ed t* reiliiee I he eUriM'Ut IliIN resist- 
anee i* UMug up pv\iT jit"*! as if it were doing useful work, 
Tin* \oltaw a? th' ttp'id ttili run from 1 to 15 volts, depending 
ou the Ni/e of iii>' U'^hter niid v\orK, To ohfaiii this low voltaic, 
ii Npceinl lrair*i'iiniif r iusi|i* lit*- lunduue n*dnceH the power 
tine voltftt*y Joutj to the wuouM reiptiretl at the wehl Tin* 
transfonio'r i fc * plaeed uiihin the fraia* of the miicltine t as 
shoU'ii iu Pif/, IMI, Tit*' ^M'ondary wiudiuK ^ the transformer 
is etiiiiiulMl In thr piufeji-i hy HM'iiiW of llexihle < t tpper Iead, 



240 



ELECTRIC WELDING 



From the platens the welding current travels to the work 
clamps and through them to the pieces to be welded. As the 
parts to be welded are brought into contact a switch is thrown 
in and the current traveling across heats the ends of the work 
and when the proper welding heat is reached the operator 



WORK STOP 



OAMP ADJUSTMENT 

CLAMP JAW WITH STEEL DIE 

" 

COPPER DIE 




CLAMP RELEASE 
CLAMP LOCKING 



Fi0, 190.- Principal Parts of a Butt-Welding Machine. 

pushes the two parts together and the weld is completed. Sinc6 
the current value rises as the potential falls in the secondary 
circuit, and since the heating effect across the work is directly 
proportional to the current value it will be easily seen why 
a transformer is necessary to produce a heavy current by lower- 



BUTT-WELDING MACHINES AND WORK 



241 



ing the line potential. Due to the intermittent character of 
the load, there is no standard rating for welding transformers, 
and different makers frequently give entirely different ratings 
for their machines. However, regardless of the rating capacity 
in kilowatts, there can be very little difference in the 
actual amount of current consumed unless an especially bad 




FIG. 191. Butt-Welding Machine with Work in Jaws. 

transformer design is used. To heat a given size stock to 
welding temperature in a given time requires an approximately 
invariable amount of current. 

The machine just illustrated, is shown at a slightly different 
angle and with two pieces of rod in the jaws, in Fig. 191. 
This is the Thomson regular No. 3, butt-welding machine. It 



242 



ELECTRIC WELDING 




FIG. 192. Details of Foot-Operated Clamping Mechanism. 




G. 193. A Hand-Operated Clamp. 




194. Toggle-Lever Clamp for Bound Stock. 



MACHINKS AND WORK 



243 



has a rapacity of rod from I to ; ; in. in diameter or flat stock- 
up to 4 /4>.2 in- " two separate pieces, or rings of Yi-m, 
stork and not less than 2 in, in diameter. Hoops and bunds 
up to V , rt \iY i- and not less than <J l / 2 in. diameter when 
held lelow flu* line of welding, may also be welded. With 
jaws specially made to hold the work above the line of welding 
a minimum diameter of" -U in. is necessary. This machine will 
produee from 150 tu 200 senarate pieces, 150 to 'MO hoops, 
or 1100 to 400 rinurs p*-r hour, The lower dies are of har<l 
drawn copper with contact surfaces l l /*X2 "i.X5i l /u " UL thick. 






L. 




ftir H*itvy Flitf Hfwk, 



Standard tru!tHh*rm-r windings are for 220, 440 and 550 volts, 
til! r\Hr fiirri-iif, t 'nrreut variation for different sixes of sto<k 
is rfjYetrd thntiiuli a Hve^pitittt switch shown at the left. 
Standard nitttifi.% are JT> K\v, or 22 kvu,, with fiO per cent power 
faefor. Th 



rr buff i- 

ir spae 

!b, A 



dirn nr* air e*inled but the chuaps to wliicli the 
ar- >\ ati-r eonb-d, Tliis type of mnebine o<etipies 
4ll > in in., and is a,*I In, higb. The weight in 
luNi- up vir-iv itf llii* treadb*-op4*rate*l ebuupiug 



in* 



iii"flit*d 



ti 



jatws diflVrK accord- 



244: 



ELECTRIC WELDING 



ing to the size of the machine and the work that is to be 
done. On some of the smaller machines the type of hand- 
operated clamp shown in Fig. 193 is used. On other machines, 
intended to handle round stock principally, the toggle lever 
clamp shown in Fig. 194 is used. For very heavy flat stock, 
the hand-lever clamping mechanism, shown in Fig. 195, is 
used. On some of the machines used on small repetition work 
the clamps and switch are automatically cam-operated as shown 
in Figs. 196 and 197. The first machine is a bench type used 




FIG. 196. A Cam-Operated Machine. 

for welding on twist drill shanks, and the second machine is 
used for welding harness rings. These jobs are, of course, 
merely examples as the machines are adapted for all sorts 
of the smaller welding jobs. Spring pressure, toggle-lever or 
hydraulic pressure are used to give the final "shove-up" accord- 
ing to the machine used or weight of stock being welded. 

In welding hard steel wire of over 35 per cent carbon 
content, it is necessary to anneal the work for a distance of 
about 1 in. on each side of the weld. This is due to the fact 



wnT-\VKU>iNt; MACUINKS AND WORK 



245 



that the wire on each side is rendered hrittle by the cooling 
effect of tin* damping jaws. To accomplish this annealing, 
nil th*' small Thomson machines used for this work art* equipped 
with it set of Y-jaws outside of t!u- damping jaws, as shown 
in front in Pig. HKS. The uuv is laid in tlu\se Y's with the 




Oil 

tftitly by tii'iiH f it puhli Iniflon until tin- wire han heeontp 

Itriitrtl to thr ttrHirmt riilur, wlirli it bf removed niid nllowed 
to eol Th*- iitiiii'iiliiig if ii Htftftll drill IH shown in Fig, 1W. 
The prongs tf wrliliim niul nnt'Hn 1- tftf*. hat-<l steel wire 



246 



ELECTRIC WELDING 




PIG. 198.- Machine Equipped with Annealing Device. 




PIG. 199. Annealing a Small Drill 



BUTT-WELDING MACHINES AND WORK 247 

requires about 30 sec. when done by an experienced operator. 
Copper and brass wire are easily welded in these same machines. 
The machine shown will weld iron and steel wire from No. 
21 B. & S. to & in. in diameter and flat stock up to No. 25 
B. & S.Xi in. wide. Production is from 150 to 250 welds per 
hour, the actual welding time being 1-| sec. on -J-in. steel wire. 
The clamps are spring-pressure, with adjustable tension 
released by hand lever. The standard windings are furnished 
for 110, 220, 440 and 550 volts, 60 cycles. Five variations are 
made possible by the switch. The ratings are 1^ kw. or 3 
kva., with 60 per cent power factor. The weight is 120 pounds. 

For use in wire mills where it is desired to weld a new 
reel of wire to the end of a run-out reel on the twisting or 
braiding machines, it has been found convenient to mount the 
machine on a truck or small bench on large casters. This 
enables one to move the welder from one winding machine to 
another very easily, to splice on new reels of small wire, the 
electrical connection to the welder being made by flexible cord, 
which is plugged into taps arranged at convenient points near 
each winding machine. It is also desirable to mount on this 
same bench a small vise in which to grip the wire to file off 
the burr resulting from the push-up of the metal in the weld. 
The average time required to weld, anneal and file up a 16-gage 
steel wire with this bench arrangement is only about one 
minute. The only preparation necessary for welding wire is 
that the stock be clean and the ends be filed fairly square so 
that they will not push by one another when the pressure 
is applied. 

In connection with welding wires and rods up to in. 
in diameter, Table XX will be found very handy. For sizes 
from |- to 2rjr in. the reader is referred to Table XXVI. 

Examples of Butt- Welding Jobs. while, as a rule, it is 
only necessary to have clean and fairly square ends for butt- 
welding in some cases where small welding is to be done it 
has been found best to bevel or V the, abutting ends. This is 
more apt to be the case with non-ferrous metals, however, than 
with iron or steel. A notable example in the larger work is 
in the scarfing of the ends of boiler tubes when butt-welding 
is done. This phase of the question has apparently not been 
given the attention it deserves, and some cases where welding 



248 



ELECTRIC WELDING 



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BUTT-WELDING MACHINES AND WORK 



249 



has been declared a failure in manufacturing may be laid 
to the fact that the parts to be welded were not scarfed and 
consequently would not stand the required tests after being 
welded. As a general rule, a properly executed butt-weld 
should, when reduced to the size cf the original section, have 
practically the same strength. 

Although copper and brass rod and strip can be welded 




FIG. 200. Typical Copper Welds. 

with perfect success, owing to the nature of the metal it 
requires a specially constructed machine to secure the best 
results. Since copper has a very low specific resistance as 
compared to iron or steel, it requires much more current to 
melt it on a given size rod. A longer time is required also 
to heat a given size of rod as compared to steel, but when 




FIG. 201. Welded Aluminum Ring. 

the plastic stage is reached the metal flows so rapidly that it 
must be pushed up with tremendous speed or the molten 
copper will flow out between the abutting ends. To effect this 
rapid push-uip of stock the platen on which the movable right- 
hand clamp is mounted must move very freely indeed, neces- 
sitating roller bearings on the larger sizes of machines. The 



250 



ELECTRIC WELDING 



pressure spring on the smaller machines must also be capable 
of maintaining its tension through a longer distance than on 




o. 202. A Steel Wire Weld. 




FIG. 203. Welded Hoisting Drum Crank Forging. 




JftO, 204. Large Welded Pinion Blank. 

a machine for iron and steel, since more metal is pushed up 

on a given size of copper rod than would be on steel or iron. 

The properties of brass and also aluminum are practically 



BUTT-WELDING MACHINES AND WOJbtK 251 




FIG. 205. Welding a Band Saw. 




FIG. 206. Baridsaw Weld before and after Removing Flash. 



252 ELECTIC WELDING 

the same as those of copper and therefore this special type 
of machine is just as well adapted for these metals. 

Typical copper welds are shown in Fig. 200. The one at 
the left shows it just as it came from the machine, and the 
one at the right with the flash partly removed. Fig. 201 
shows an aluminum ring immediately after welding. A steel 
wire weld is shown in Fig. 202, and a welded hoisting drum 
crank in Fig. 203. This last illustration shows how some 
drop forgings may be simplified and the cost of dies and 
production lessened. A large pinion gear blank is shown in 
Fig. 204. Made in this way, a large amount of time and metal 
is saved. The way to weld pieces of large and small cross 
section is described in the article on tool welding. 

Band saws may be butt-welded as shown in Fig. 205. The 
way a band saw looks after welding and after the flash is 
removed is shown in Fig. 206. 

T-WELDING 

T-welding, which is a special form of butt-welding, is, as 
its name implies, the process of making a weld in the shape 
of the letter "T". Where it is desired to weld a piece of 
iron to the middle of another bar of equal size or larger, it 
becomes necessary to heat the top bar of the "T" to a bright 
red; then bring the lower bar to the preheated one and again 
turn on the current, when a weld can quickly be made. The 
reason for doing this is as follows : The pieces are of unequal 
area in cross-section at the junction of the two pieces. As 
it takes longer to heat the upper part, the end of the lower 
part of the "T" would biirn before the upper piece would 
reach the welding temperature. Preheating will equalize and 
overcome this difficulty. Special machines known as "T" 
welders are built for this class of work to facilitate the pre- 
heating, when the highest possible production on this form 
of weld is desired. 

Automobile Rim Work. One of the largest applications of 
butt-welding today is to be found in the automobile-rim in- 
dustry. The special form of clamp shown in Fig. 195 was 
especially designed to handle rims of all kinds and sizes. It 
is not adaptable for any type of work other than flat stock, 



HlTT-\VKia)IN<i MACHINES AND WORK 251$ 

as the amount of jaw opening is much smaller than the diameter 
of equivalent section of round stock. 

No backing-up stops of any kind are built for these machines 
with rim-clamps, as stops arc unnecessary for this class of 
work. In order to secure sufficient gripping effect of the stock 
to prevent it slipping in the clamp-jaws, the upper dies arc* 
made of self-hardening steel with the gripping surface cor- 
rugated. The lower dies, which carry all the current to the 
work, art 1 made of copper with Tobin-bron/.e shoes on which 
the work rests, so as to give good conductivity and yet present 
a hard wearing surface to the steel rim. These lower dies 
must not only bear the gripping effort exerted by the steel 
dies above, hut also the weight of the rim, which, in large* sixes, 
amounts to considerable. 

The method employed in welding automobile rims is the 
"flush-weld" principle, wherein the current is firs! turned, on 
with the edges to be welded pulled apart. The pressure is 
then applied gently to bring the abutting ends .slowly together. 
AH uneven projections come into/ contact across from opposite 
edges they nre burned or "flushed" off, \vhieh is evidenced 
by f lying particles of burning Iron, The- pressure is gradually 
increased, bringing more of the length of the opposite edges 
into contact and when the **JIash" thrmvs out for the full 
width of the rim which indicates I be abutting nids art* touch- 
ing all the wiiy across, the final pres^urr is ffttiekly applied 
as tin* current is turned off, thereby completing tin* wrld, It 
has been found that experienced operators on thin kind of 
work do not look at the weld itself but govern their art ions 
by the appearance of the amount of (lash or sparks thrown 
out. When this assumes the shapt* of a complete f^n they know 
it JH the right moment to rut t*lY the current and apply tho 
fluid pressure. 

The burr or fin thrown up in thi type of wrld IH very 
fthort ami very brittle, making its removal much <*ast<*r than 
would he the dine with tin* heavy burr resulting from it slow 
butt-weld. It is tin' common practice in rim plants to remove 
the burr while it is Mill hot and with pn'unnttic chine! or 
a Hpru* culler. The slight amount of littrr then remaining 
in ground of? with a coarsi' abrasive wheel and the rim Js ready 
for tin* forming pro<t-,H. In most rim phtntn flit* oprratioim 



254 



ELECTRIC WELDING 



of rolling, welding, chiseling burr, grinding burr, formir 
shaping, etc., fit in so closely to one another that a rim 
practically kept moving continuously from the time the fl 
stock is put into the rolls until a finished rim emerges. T 
welding operation itself on a rim blank for 30 X3^ tire si; 
for instance, has an average production rate of 60 rims p 
hour, some concerns doing even better than this. On lar 




FIG. 207. Truck Bim Welding Machine. 

truck rims for solid tires, having a section of 16 Xf in. thic 
a production of 10 rims per hour is considered very goc 
although there are concerns doing even better than this 
such heavy work. 

The machine shown in Fig. 207 was specially designed i 
handling heavy truck rims only. The lower jaws on tl 
welder are placed very low in order that, the machine c 



BUTT-WELDING MACHINES AND WORK: 



255 



be set in a comparatively shallow pit to bring the line of 
weld on a level with the floor. This makes it possible, with 
proper tracking arrangements, to roll heavy rims right onto 
the lower dies without any lifting, the rim being rolled out 
again after welding. The double oil-transformers used in this 
welder hang below the base line, which necessitates a small 
pit directly under the center of machine. Owing to this and 
also the weight to be supported, a concrete foundation only 
should be employed. 

This machine has a capacity for stock |X8 to |X16 in., 
or a maximum thickness of 1 in. with a cross-sectional area 
of not over 7 sq. in. Rims with a minimum diameter of 30 in. 
can be welded. The pressure is effected by twin hydraulic 




FIG. 208. A Heavy Welded Bim. 

cylinders operated from an external accumulator giving a 
maximum pressure of 24 to 37 tons on the work. The voltage 
windings are of the same capacity as for other machines. The 
transformer is of the oil cooled type, and the ratings are 160 
kw. er 266 kva., with 60 per cent power factor. Primary 
windings of transformers are submerged in cooling oil con- 
tained in casings. Platens on which the clamps are mounted 
and the bodies of the lower jaws to which the contact shoes 
are bolted, are water cooled. This machine is 66X101 in. and 
66 in. high. The net weight is 14,000 pounds. 

A heavy rim after welding is shown in Fig. 208. ^ 
Welding Pipe. In order to weld pipe and tubing in the 
form of coils for condenser systems cooling tubes, heating 
coils, etc., as shown in Fig. 209, it was found necessary to 



256 



ELECTRIC WELDING 



employ a special form of clamp wherein the jaws could 
set up high to give clearance above the pressure-device. 1 
thickness of the die and die-block to which it is bolted a 
had to be reduced to a minimum so as to insert the ja 
between coils, since the pipe is coiled through each length a 
then another length is welded on, which in turn is coiled, a 
so on. In order to secure the best gripping effect with 
comparatively light die, it is necessary to make this form 
die considerably longer than those used in the -other ty] 




FIG. 209. Welding Pipe Coils. 

of horizontal-acting clamps. Moreover, since there is r 
enough space in the narrow block to which the die is bolt 
to permit water circulation, the die itself must be water-cool 
to prevent softening of the copper from continued contact wi 
the hot pipe just in back of the weld. 

This type of clamp, Fig. 210 ; is designed for welding 
pipe and tubing only, which requires a much lighter pressv 
to push up than solid stock of the same cross-sectional ar< 
and since the line of weld is considerably above the line 
pressure, the slides will be quickly worn on the movable plat 
if heavy pressure is used continually. For this reason t 



ii \\muvi 



-is AND WORK 




258 



ELECTRIC WELDING 





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External 


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Actual 
Internal 


f C-J t- IO OC rH O 
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Nominal 
Internal 


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External 


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Diameters 


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Internal 


iO -H rH OJ O rH CJ -H CO IO CJ 00 

ci <N TH 10 i- o CM -H c: co CXD co 

rH rH rH <>{ Cl CO 






Nominal 
Internal 


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Actual 
External 


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Diameters 


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HHHHCO^HCO ^ N *' OOb-00 COCO 

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Nominal 
Internal 


\00 \f \00 VN \^l \^( SM VJN \^, ^M 
rH THrHCl (NCOCO '^^ 



! MACHINES AND WORK 



259 



Yn\g of any solid stock with this class of machine Is not 
isable. 

Phe machine shown will weld iron and stool pipe from :J 

in. iu diameter, ordinary pipe sizes and H in. extra heavy 

', or double heavy 1 in. iu diameter. Standard steel tubing 




Fid. 21U.A <lt*mrttl Pwrpono Butt-WaMmg 



n 1 to 2| in. diiniieter may be welded. Pressure m sttppHed 
fi Iiydrnulie oil ju<*k (x<*rtlnjjf a maximum of 5 tons. The 
ttlnrd ratings are '!() kw. or 50 kvu., with pow<r Factor of 

H*r et-nt, Th** maehiuf* will w<*igh about 25(K) pounds. 
[Air welding pipe. Table XX I. will bo found useful for 



260 ELECTEIC WELDING 

reference purposes. - This table was compiled by the Thomson 
Electric Welding Co., with special reference to their machines. 

Winfield Butt- Welding Machines. The Winfield Electric 
Welding Machine Co., Winfield, Ohio, makes a complete line 
of butt-welding machines but only a few representative of 
their line, will be shown. A very convenient portable or bench 
type is shown in Fig. 211. This is especially useful for light 
manufacturing work. It has a capacity of 18 to 6 gage wire. 
It is equipped with a 1 kw. transformer, hand clamping levers 
and a 3-step self-contained regulator for controlling the cur- 
rent. It occupies a floor space of 13-JX16 in., is 35 in. high 
from floor to center of welding dies, and weighs about 130 Ib. 
complete. 

The machine shown in Fig. 212 is for general all-round 
shop work. It has a capacity of from J to 1 in. round, or 
j}X2 in. flat stock. It has a 25-kw. transformer, water-cooled 
welding jaws, enclosed non-automatic switch on upsetting lever, 
stop for regulating amount of take-up on each weld, ten-step 
self-contained regulator for controlling the current, occupies 
a floor space of 44X25 in., is 42 in. high to center of jaws and 
weighs about 1,800 Ib. The jaws overhang as shown, for 
welding hoops, rings, rims, etc. 

The machine shown in Fig. 213 is for toolroom work and 
was especially designed for handling large, cross-sections. It 
will weld up to 2-| in. round. All clamping and upsetting 
operations are accomplished by means of air or hydraulic pres- 
sure. The clamping cylinders are operated independently of 
each other by means of separate valves, which enable the 
operator to clamp each piece before the current is turned on. 
The small air cylinder on the right-hand end of the machine 
keeps the work in close contact during the heating operation. 
The final pressure is applied by the hydraulic ram after the 
proper welding heat has been attained. The table at the left 
is equipped with adjustments for moving it up or down, back 
and forth, tilting or twisting. This feature is especially valu- 
able in experimental work and often saves buying a special 
machine for unusual manufacturing jobs. The terminals are 
cooled by a stream of water which flows from one to the other. 
The dies are held in place by slotted clamps which permit easy 
removal. Work stops and stops to regulate the amount of 



IU T TT-AYKLIHX<; M.U'IUXKS AND WORK 



261 



upset arc provided. The movable table "is fitted with rolle?* 
bearings to insure easy operation. The transformer is a, Win- 
field 12.1 kw. The machine has a ten-step current regulator., 
and the current Tor welding is controlled by a Cut ler-llammer 
magnetic switch which in turn is operated by means of a 
small auxiliary switch placed on the valve lever controlling 
the hydraulic* ram. The floor space occupied is (>O v iK) in., and 
the approximate weight, ready for shipment, is 8,001) Ib. 




Toolroom Mwhiw*. 



Tnblr XXII compiled by this concern contains some useful 
tiatn not given in the other tables. 

Federal Butt- Welding Machines. The machines built by 
tht Federal Machine niut Wt-Ulrr ('(K, WIUTCIU Ohio, do not 

differ in the pntn-iptrs of openitioit From the machines already 
described. The furw f tin* one shown in Fig, 214, however, 
differs coiiHtdernbly from any .shown. The tables, or platens, 
lire lint and are T-stuttcd HO that various fixtures may be easily 
bulled in ptnce. The maximum capacity for continuous service, 
is *2\ in, munl <*r other sliape of e<jiml section. Flats up to 



262 



ELECTRIC WELDING 



X10 in. may be welded. The platens arc of gunmctal and 
the T-slots will take -in. bolts. These platens are recessed and 
water-cooled. Pressure is applied by means of an hydraulic 
jack, shown at the right. The switch is remote control mag- 
netically operated. The main switch is controlled by a small 
shunt switch which is worked either by hand or foot, as desired. 
The transformer is 100 kva. It has an eight-step regulating 
coil. Floor space occupied is 38X88 in., height 50 in., weight 
5,600 Ib. Tliis machine is intended to weld auto-rims, heavy 
forgings, steel frames, shafting, high-speed steel and work 




FIG. 214. Federal Heavy-Duty Butt-Welding Machine. 

requiring accurate alignment and rapid production in quan- 
tities. 

A set consisting of a tube welder and roller is shown 
in Fig. 215. This will weld tubes from 1 to 3 in. It will 
also weld flat, round or square stock of equivalent cross section. 
The dies are water-cooled, and the work is clamped in position 
by air cylinders operating on a line pressure of 80 to 100 Ib. 
The switch is on the main operating lever, so that the heat 
is at all times under the control of the operator. The trans- 
former is 65 kw. air cooled. Eight current steps are obtained. 
The machine occupies a floor space of 30x51 in., is 42 in. high, 
and weighs 2,100 Ib. By using the set, a tube may be welded 
and immediately transferred to the rolling machine and the 



BITT-WKLIMNC; MACHIN'KS AND WORK 



263 



TAHI.I-; XXII. COST OF | TO 2 ix. WKLIKS PKU THOUSAND 















Labor 


Arm iu 






Time 


CoKt, Per 


AvrniKr 


C()Ht 


Diameter Sjtuue 


K, W. 


Home 


in Se<\ 


1000 Wehln 


No. 


Per 1000 


of Stork Iiu'lii-;. 


Heqnire<I 


Power 


Per 


:it. I <. Per 


of Welds 


at HOC. 








Weld 


K.VV. Hour 


Per Hour 


Per Hour 


7, Inch .05 


l! 


,'J 


a 


.OH 


too 


.75 


V.. " - ns 


> 


4 


4.5 


.05 


175 


.SO 


V, " " 


4 


5 


(J 


.07 


150 


.85 


7.< " .I.'. 


5 


7 


(5.5 


.10 


>00 


1.00 


7, " -*' 


t> 


S 


7 


.in 


J50 


l.HO 


v / iA ' * .!!." 


7 


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7,5 


.15 


1100 


1.50 


V, " .."i 


S 


11 


S 


.18 


150 


H.OO 


"/ " :1 " 





rj 


1) 


.H3 


I.'IO 


H.iU) 


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10 


1:1 


10 


.us 


100 


:t.oo 




10.5 


14 


in 


.."55 


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15 


15 


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15,5 


17 


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111 


H> 


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n.70 


7, " .! 


Hi 


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75 


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7, - 1,1:,". 


l! 


115 


25 


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70 


4.:io 


V, ** i.-is 


115 


M,l 


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li.OS 


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7, - 1.77 


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41 


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5.00 


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51 


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5.50 


v* 4< - 


45 


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40 


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7! 


\:\ 


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40 


7.50 


J ' .1.1! 


rn 


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45 


7.50 


:io 


10,00 



flash rolled tint. Thr tini*' <Miisuint'(l in rollinj*; down the Hash 
uin* is givrn as apju"ox"unat(*ly 20 sccoiuls. 




Fsti, 'JI.V- A Tulii'-WrliUnj? Hot. 

Welding Rotor Bars to End Rings. -In th< fieneraJ Electric 
Rnnnc Cor I)iri*!iil.H*i\. I!HH, K. R ColIinH and \V. Jacob describe 



264 



ELECTRIC WELDING 



the welding of rotor bars to the end rings used in squirrel-cage 
induction motors, employing the machine shown in Fig. 216. 
This machine has a double set of welding jaws, the front set 
being used to butt-weld end rings to make them seamless, 
while the rear set is used to weld the rotor bars to the end 
rings. As shown, the machine is welding rotor-bars to the 
end-rings. The description of the work as carried out- in the 
General Electric shops is as follows : 

"The projecting rotor bars surround a toothed end ring, 




FIG. 216 General Electric Machine for Rotor Work. 

which is of slightly smaller diameter than the rotor. A small 
block of copper is placed so that it covers the copper end 
surfaces of a rotor bar and the corresponding tooth on the 
end ring, after which it is butt-welded into place. 

The projecting rotor bars are shown at A in Fig. 217 and 
the toothed end ring just inside the circle of rotor bars is 
shown at B. Finished welds as at C show blocks in place. 
The actual operation is as follows: A rotor bar is tightly 
clamped to the corresponding tooth of the end-ring between 
the jaws D and E. The copper-block end-connection is placed 



BUTT-WELDING MACHINES AND WORK 



265 



that it covers the combined area of tooth and bar ends, 
le movable jaw F holds the end connection in place, and 
avy pressure is then applied through compression springs. 
le welding current, furnished by a special transformer having 
one-turn secondary, passes from jaw F through the surfaces 
id out through jaw E. This heavy current at low voltage 
uses intense heating due to the comparatively high resistance 




PlG. 217. Details of the Welding Mechanism and Work. 

; the surface junction, and raises the temperature of the 
>pper to welding heat, at which point the metal is plastic. 

At this stage spring pressure forces the jaw F toward the 
itor and squeezes out any oxide which may have formed 
rtween the welding surfaces. A small stream of water, play- 
,g iipon the hot area, forms an atmosphere of super-heated 
earn which prevents the formation of oxide and also guards 
gainst excessive heating of vhc copper. No flux is used in 
ie operation as the mechanical squeezing-out of the oxide 



266 ELECTRIC WELDING 

is sufficient to form a homogeneous connection between the two 
surfaces. 

As the welding jaws approach one another when the metal 
becomes plastic, an electrical connection is automatically made 
which operates a solenoid-controlled switch that opens the 
primary transformer circuit. Thus the current is interrupted 
as soon as the surfaces have knitted together. The contacts 
of this automatic switch are placed one on each movable jaw, 
and are so adjusted that they are separated by the distance 
necessary for the jaws to approach one another in forming 




FIG. 218. Butt- Welding the End Kings. 

the weld and in forcing out the oxide. In this way, the end 
connection is butt-welded to the rotor bar and the end ring, 
forming a junction of great mechanical strength and low 
resistance. 

Another example of non-ferrous butt welding is the making 
of seamless end rings, which operation is performed in the 
same machine. The operation is shown in detail in Fig. 218, 
which shows a finished end ring in place. One end of the 
ring is placed in the vise-jaws G and H, and the other is held 
in the opposite jaws I and /. As the jaws approach pressure 
is applied by means of the springs. In all other respects the 
operation is similar to that of welding the end connections. 



BUTT-WELDING MACHINES AND WORK 267 

Rotors up to 14 ft. in diameter are welded and Fig. 219 
hows the rotor for a 1,400-hp. motor being welded. 

The work is done rapidly; for example, end connections 
dth a welding surface of about 0.6 by 0.4 in. are welded at 
lie rate of about 90 an hour. 

Welding 1 Brass, Brass rotor bars and end rings are also 
utt-weldcd in a similar manner, but the operation is slower. 
rass, being an alloy, has a lower melting point than copper, 




FIG. 219.- Welding End Eing and Kotor Bars for 1400-H.P. Motor. 

rid less pressure is necessary to effect a weld. The pressure 
i determined by the thickness of the piece to be welded, and 
lould be just enough to form a small "flash" at the point 
union. Excessive pressure will cause the molten metal to 
jurt out from the point of weld. In one fundamental 
articular the butt-welding of brass differs from that of copper, 
ic pressure on brass must not be released after the stoppage 
f current until the metal has hardened sufficiently so that it 
ill not crack on cooling. This delay retards the rate of 
r elding to the extent that about 60 brass end connections, 



268 



ELECTRIC WELDING 



of the size previously mentioned, require the same time as 
90 of copper. 

Butt-welding* has been the means of producing a rotor hav- 
ing low resistance, high mechanical strength, and ability to 
permanently withstand vibration and centrifugal force without 
excessive heating, all of which are essential factors in an 
efficiently operated squirrel-cage induction motor. 

WELDING ELBOWS ON LIBERTY CYLINDERS 

In making Liberty motors in the Ford shop, the valve 
elbows were butt-welded on as shown in Fig. 220. The holding 




FIG. 220. Welding Valve Elbows. 

fixture is shown with the hinged top thrown back and a 
cylinder in the cradle. One elbow has already been welded 
on, and the other is held in the jaws of the sliding fixture, 
ready to be welded in place. This work was done before 
the cylinders were finish bored and by so doing all cylinder 
'distortion, due to welding was cut out in the finish boring. 

An automatic straight-link chain making machine, built by 
the Aiztomatic Machine Co., Bridgeport, Conn., is shown in 



BUTT-WEL)ING MACHINES AND WORK 269 



, 

tined ti T ^ butt ' weldcd the e ^s of the links and 
mned out the chain as indicated. The machine was so made 
that the welded part of each link was pressed between special 
dies whale still hot, the operation practically eHmina ing th 




PIG. 221. Automatic Chain Making Machine. 



flash formed in welding. Aside from the welding features, the 
machine was a marvel of mechanical ingenuity and simplicity. 

ELECTRO- PERCUSSIVE WELDING 

The joining of small aluminum wires has always presented 
much difficulty on account of the oxide film which prevents 
the metal parts from flowing together, unless brought to a 
point of fluidity at which the oxide film can be broken up 
and washed away. If this be attempted with small sections, 
the whole mass is likely to be oxidized, and the resulting joint 
will be brittle or " crumbly. " 

In 1905 L. W. Chubb, of the Westinghouse Electric and 
Manufacturing Co., Pittsburgh, Penn., discovered that if two 



270 



ELECTRIC WELDING 



pieces of wire were connected to the terminals of a charged 
condenser, and then brought together with some force, that 
enough electrical energy would be concentrated at the point 



A- 




FlO. 222. Electro-Percussive Welding Machine. 

of contact to melt the wires, while the force of the blow 
would weld them together. Accordingly, a welding process 
was developed and used by the Westinghouse company, and 



BUTT-WELDING MACHINES AND WORK 



271 



machines made which arc capable of welding all kinds of wire 
up to No. 13 gage. The process was called electro-percussive 




Fro. 223. Details of Percussive Welding Machine and Wiring .Diagram. 

welding and a machine for doing the work is shown in Fig. 
222. This machine has vertical guides A between which travels 



272 ELECTRIC WELDING 

a chuck B holding one wire C. The other wire is held below 
in chuck D in such a position that the end of the moving wire 
strikes it squarely. Each chuck is connected by flexible cable 
to a circuit as shown in Fig. 223. An electrolyte condenser 
A, shown in the wiring diagram, is connected across a source 
of direct current from B, which charges it to a potential 
determined by the resistances C and D. -A switch E 
keeps the chucks F and G at the same potential during place- 
ment and removal of work. 

After the wires to be welded have been chucked, they are 
clipped short by a cutter which gives each a chisel, or wedge- 
shaped end. These ends are set at right angles to each other. 
The switch is opened and the sliding chuck is released and 
allowed to fall. At the instant when the two narrow edges 
come into contact, the current discharged generates intense 
heat at the center of the section. The metal melts and is 
forced out by the impact and eventually the entire surface 
of each wire is melted. Due to the very large body of cold 
metal adjacent, the thin film of molten metal solidifies quickly 
and since it is under momentarily heavy pressure it forms a 
homogenous mass absolutely continuous with the wires on 
each side. In practical operation, the. inductance II is required 
to lower the rate at which the condenser discharges, that is, 
to maintain the current at a lower rate until the entire surface 
of the weld has been forced into contact. The correct action 
can be told by the sound made by the contact. It should be 
a splash or thud, rather than a sharp crack. The mass and 
drop of the falling part must be great enough to slightly forge 
the material. Once set for the proper drop, the machine will 
make a perfect weld every time. 

Actual tests on two No. 18 B. & S. aluminum wires, using 
an oscillograph, show that the power being expended at the 
weld reaches a value of 23 kw. for an instant. However, the 
entire weld is made in 0.0012 sec., and the total energy used 
at the weld is 0.00000123 kw.-hr. The cost of this weld, figured 
at 10 cents per kw.-hr., would be twelve millionths of a cent. 

A chart of the oscillograph aluminum-wire test just referred 
to, is shown in. Fig. 224. At A the right-angled chisel-ends 
are shown almost in contact as the upper chuck falls. As the 
ends contact at B the voltage drops as indicated by the curve 



WTT- \VKLIHNO MAOHINKS AND WORK 



6\ hut the current and power consumption suddenly increases 
as shown hy the curves // and / respectively. 

At ( the wire ends have separated, caused hy the melting 
and vapori/.ing of the chisel edges. At D the chucks are closer 
together hut the arc is still hurtling away the \vire ends. At 
K the second contact has heen made, the arc. eliminated and 
upsetting begun. At /*' the* weld is shown completed. 

One of the principal uses for this process is in welding 
copper to aluminum, as for example copper lead-wires to 




ABC 

, 'iwrt uf UwiUnuwph T*M mi is U. 

ujir I*MW,i j i < *jtHtit}ii'| uttd TIJIH* to (Nuiij 



S, <iur AUiminum Wire, 
t*' it IVrc-uHHivo Well, 



iiliunhiiiiii -otls. Tlie advantage of copper for eotniectiiiK is 
Hflf^viilmt. as it is rnsily soldered, It was thoiiKht at first 
that n wi*hl of the two untals would result in a brittle joint, 
hut trM* show that after xeveral yenrn tlie joint is apparently 
as Mining ami ttnctite an when first made. Similar ductility 
has luM'ii ntrl in almost every combination of metals wlien 
first xvrhliMl, hut ilisJutr^ration and loss of ductility eventually 
result in su*h wrlds us ailver to tin or aluminum to tin, the 
wi'hls hi'iiiu: nlTeetiHi hy what is known as "tin disease" or 
**tin prst " it titHinte^rntlon of tlie moleculeH. 



274 



ELECTRIC WELDING 



Alloy of practically any composition can be welded to each 
other, and there is little diffusion of one metal into the other 
across the welded surface. Thus this method is quite suitable 




225. Copper Welded to Aluminum. 



for attaching contact points to flat plates and making small 
welds required "by jewelers. 

Another important quality of the process is that metals 
which soften with heating, such as hard-drawn copper and 



BUTT-WELDING MACHINES AND WORK 275 

:', can be welded without change of condition since the 
li of metal heated to an annealing temperature will not 
.ore than 0.004 in. long and this amount of metal is neg- 
ly small. As will be seen from the specimens in Pig. 225, 
h show copper welded to aluminum, then drawn and rolled, 
i is no loss of ductility at the weld and no tendency for 
wo metals to separate. 



CHAPTER XIII 
SPOT- WELDING MACHINES AND WORK 

Spot welding, as the name indicates, is simply welding in 
spots. Two or more overlapping metal plates or sheets may 
be welded together at intervals, by confining electric current 
to a small area of passage by means of suitable electrodes, 
or "dies" which are pressed against the metal from opposite 
sides. Spot welding is a form of resistance welding. Due to 
the way the metal is heated and forced together no oxidizing 
takes place, and in consequence no flux of any kind is needed. 

While the process of spot welding is more commonly used 
at present for welding thin sheet iron, steel or brass articles, 
practical machines have been made for welding two pieces 
of 2-in. ship plate together. Experimental machines have also 
been made capable of spot-welding three 1-in. plates together, 
and which can exert a pressure of 36 tons and have a current- 
capacity of 100,000 amperes. 

To weld soft cold-rolled steel in a satisfactory commerci*il 
manner, three conditions should be observed, if possible: 

First, the surfaces to be welded should be free from rust, 
scale or dirt. If the work is not clean a higher secondary 
voltage will be required to penetrate through the scale or dirt 
of any given thickness of sheet. This means that a larger 
machine and more current must be used than would be required 
for clean stock of the same thickness. 

Second, the sheets should be flat and in good contact at 
the spots to be welded, so that no great pressure is required 
to flatten down bulges or dents. 

Third, the stock should not surround the lower horn, as 
in the case of welding the side seam of a can or pipe. 

It must not be understood that spot welding cannot be done 
except under the conditions outlined, for it can, but if the 
conditions named are not followed the cost of welding will 
be greater. However, it is often necessary to violate these 

276 



SPOT-WELDING MACHINES AND WORK 277 

iditions in actual manufacturing work. This is especially 
.e of the third one. Where the lower horn must be sur- 
mded by the work, as in welding can seams, the capacity 
the machine is cut down because of the "induction effect" 
ich tends to choke back the main current and in this way 
;s down the heating effect at the die points. This so-called 
luction effect is only present when welding steel or iron, 
such action being noticeable in welding brass. 
Light gages of sheet metal can be welded to heavy gages 
to solid bars of steel if the light-gage metal is not greater 
in the rated single sheet capacity of the machine. Soft^steel 
d iron form the best welding material in sheet metals, al- 
nigli it is possible to weld sheet iron or steel to malleable-iron 
tfings of a good quality. 

Galvanized iron can also be welded successfully, although 
takes a slightly longer time than clear iron or steel stock, 
order to burn oft' the zinc coating before the weld can be 
ide. Contrary to common opinion, the metal at the point- 
weld is not made susceptible to rust by this burning off 
zinc, since by some electrochemical action it has been found 
it the spots directly under each die-point and also around 
: point of weld between the sheets, are covered with a thin 
ating of zinc oxide after the weld has taken place. This 
iting acts as a rust preventive to a very noticeable degree, 
i spot-welded articles used in practice for some time, such 
galvanized road-culverts, refrigerator-racks and pans, rain- 
tters, etc., it has been found that no trace of rust has ap- 
arcd on the spot-welds from their exposure to ordinary 
rnospherie conditions. Extra light gages of galvanized iron 
low 28 P>. & S. gage cannot be very successfully welded, due 
the fact that so little of the iron is left after the zinc has 
en burnt off that the metal is very apt to burn through 
d leave a hole in the sheets. 

Tinne^shect iron isjdeal for^welddng^giving great strength 

the weld, but the stock will be discolored over the area 

vered by the die-points. Sheet brass can be welded to brass 

steel if it contains not more than 60 per cent copper. It 

not practical to attempt to spot-weld any bronze or alloy 

ntaining a higher percentage of copper than this as the weld 

ill be weak. 



278 



ELECTRIC WELDING 



Another class of work that can be successfully handled on 
a spot-welding machine, although it is not strictly spot welding, 
is the construction of wire-goods articles. This consists prin- 
cipally_jaJ/ mash-welding " crossed wires. It may be done 
with the same copper die-points as are used for ordinary spot 
welding, except that the points are usually grooved to hold 
the wire in the required position. Among the common wire 
goods put together in this way are lamp-shade frames, oven 




FiG. 226. Typical Construction of Light Spot-Welding Machine. 

racks, dish drainers, waste baskets, frames for floral make-ups 
and so on. Certain classes of butt-welding may also be done 
on a spot-welding machine by using special attachments. 

Details of Standard Spot- Welding Machines. Spot-welding 
machines are made in various sizes and designs to meet dif- 
ferent requirements, but the general principle of action is the 
same in all. The illustration, Fig. 226, shows a Thomson No. 
124-A10 machine with the cover removed. This gives an idea 
of the principal mechanism of all this line of light spot-welding 



JMAUIUNKS AND WORK 



279 



hinos. Kijr. >7 shows a typical head of one of their line 
heavier machines. This type of machine is designed for 
vy work^on flat sheets or pieces, where considerable pros- 
> is required to bring Hie parts together to he welded. To 
hsiand heavy pressures, the lower horn is made of T-soetum 
iron and the current is conducted to the lower copper 
holder hy flexible copper laminations, protected oil all sixes 



SWITCH OH coMPRcwi^N'Tifl^irrSTSlrSo WHEN AUTOMATIC 

.SWITtM IS CUT OUT & MO&f. THAN M30 LB3. 15 OtSIRCD 



COMPRESSION LEVER QEMAIN5 IN UPPER 
POMTIOH WHEN U5IHG FOOT TREADLE 



COMPRESSION UVt : R COUNTER 

*" IVU AN CL WEIGHT 



10 POINT M*lf CON- 
TAINFO fJhfULATOW 



01 Itrtf CU^f/!HI n ON 
5tl| IN I 



f(r Heavy Work, with I'urtH 




ing over la-in. thnutt, by a brass cover, insulated on the 
df from I tie copper by a coating of asbestos short. 
The htitiinjjt li**ad of the machine which carries the upper 
holder is ii hollow steel plunder, sliding* in a cant -iron head, 
eh bolts to the bucly of the machine and on which are 
iiifed the control-switches. The pressure is applied by a 
above the plunger, actuated both hy a swiveled 
on top of the head, which may ho swung into any 



280 ELECTRIC WELDING 

position through an arc of 260 dcg., and a foot-treadle at the 
base, which also may be swung in an arc of 30 deg. This 
enables the operator to control the machine by hand or foot 
from any position around the front of the machine. 

The current-control can be set to work automatically with 
the downward stroke of the upper die. In this case the pres- 
sure at the die-point is through an adjustable spring-cushion 
in the hollow cylinder-head. The current is automatically 
turned on after the die-points have come together on the work 
by further downward pressure of either lever. With the ap- 
plication of final pressure, to squeeze out any burnt metal as 
the weld is forced together, the current is automatically turned 
off. When working on pieces where more pressure is required 
to bring the parts together before welding than can be effected 
by the spring-cushion without turning on the current, it is 
possible to set a plug in the head of the machine so that 
direct connection is obtained from the hand-lever to the upper 
die-point while the foot-treadle still operates through the 
spring-cushion and with the automatic current-control. When 
it is desired to secure maximum pressure, the plug in the 
head can be set again so that both the hand-lever and the 
foot-treadle give direct connection to the die-point, the current, 
being controlled by a push-buttom on the outer end of the 
hand-lever. 

The regular line of spot-welding machines of different 
makes, operate on 110-, 220-, 440- and 550-volt, alternating cur- 
rent. A welding machine of this kind can only be connected 
to one phase of an a.c. circuit. The transformer must be made 
to furnish a large volume of current, at a low voltage, to the 
electrodes. For further transformer details, the reader is 
referred to the article on butt-welding. 

The Thomson Foot-, Automatic-, and Hand-Operated 
Machines. The machine shown in Fig. 228 is representative 
of the Thomson line of small, foot-operated spot-welding 
machines. These are intended for use on light stock where 
but little pressure is required. The die-holders are water- 
cooled, and the lower horn bracket allows the horn to be 
adjusted up or down for the use of various kinds of holders. 
The automatic switch and adjustable throw-in stop are plainlv 
shown at the back of the machine. 



SPOT-WELDING MACHINES AND WORK 



281 



Fhe model is made in several sixes. The first size will weld 
a 30 to 16 B. & S. gage galvanized iron or soft steel, or 
M gage brass. It will mash-weld wire from 14 gage to 
L. in diameter. Its throat depth is 12 in.; the lower horn 
p clearance is 9 in,; size is 22X45X51 in. high; net weight 




FIG. 228. The Thomson Light Manufacturing Type Spot- Welding 

Machine. 

i25 lb. ; full load rating is 5 kw., or 8 kva. The largest 
>hine of this particular series, will weld 26 to 7 gage, B. 
1., galvanized iron or soft steel, or 18 gage brass; it will 
ih-weld 10-gage to f-in. diameter wire ; has an 18-in. depth 
:hroat; is 28X60X56 in. high; weighs 1,550 lb. and full 
i rating is 15 'kw. or 25 kva. 



282 



ELECTRIC WELDING 



On repetition work, where the operator has to work the 
foot-treadle in rapid succession for long periods, it is very 
tiresome. For such work, power-driven machines similar to 
the one shown in Fig. 229 are made. These machines are sup- 
plied either with individual motor drive or pulley drive, as 
desired. The control is effected through the small treadle 
shown. The regular foot-treadle is used while setting up dies, 




FIG. 229. The Thomson Semi- Automatic Type Spot-Welding Machine. 

etc. If the operator desires to make but one stroke, he depresses 
the shorter treadle and immediately releases it, whereupon the 
machine performs one cycle of operation, automatically turn- 
ing on the current, applying the pressure, turning off the 
current, and stopping. A - to -J-hp. operating motor is used 
according to the size of the machine. Otherwise the capacity 
of the various sizes is the same as in the regular foot-operated 



SPOT-AYKIJMNG MACHINES AND WORK 283 




Ftu. *J:;o. A Thomson IIoavy-Duty SpotAVt i llinjj; Machine. 




Fin. 2;u.< Bpot-Wt'Miiig a Hhcot HUol Box* 



284 



ELECTRIC WELDING 



machines. The lower horn and upper arm may be of either 
style illustrated. 

The machine shown in Pig. 230 is a hand-lever operated 
machine, although supplied with a foot-treadle which can be 





FIG. 232. Showing How the Horn and Welding Points May Be Set. 

swung back out of the way when not needed. This machine 
is typical of the Thomson designs used for the heavier run 
of commercial work. On the various sizes, the capacity for 
spot-welding is from 22 B. & S. gage galvanized iron or steel 




FlG. 233. Welding Small Hoe Blades to the Shanks. 

up to No. gage, or to 14 gage brass. Mash-welds may be 
made on from -J- to f-in. diameter wire. The throat capacities 
run from 15 to 51 in. and the lower horn adjustment is from 
12 to 24 in. The smallest size is 28X62X75 in. high and the 



POT-\YKhI)!N(i MACHINES AND WORK 



283 





286 



ELECTRIC WELDING 




FIG. 236.- Butt- Welding Attachment for a Spot- Welding Machine. 




237. Welding Galvanized Iron Pipe. 



SPOT-WELDING MACHINES AND WORK 



287 



largest size 28X98X75 in. high. The weights run from 2,335 
to 3,225 and the full load ratings from 20 to 40 kw. or 35 to 
67 kva. Various shaped horns, dies and other equipment are 
furnished to meet special demands. 

Examples of Spot- Welding Work. In connection with the 
Thomson machines, the welding of the corners of a sheet-steel 
box is shown in Fig. 231. The illustrations in Pig. 232 show 
how the lower horn is raised for welding side seams and 
dropped for welding on the bottom of a box. 

The welding of small hoe blades to the shanks is shown 




FIG. 238. Welding 12-Gage Iron for Guards. 

in Fig. 233. These are welded at the rate of 840 per hour, 
the shanks being bent afterward. Stove-pipe dampers are 
welded as shown in Fig. 234, and wire lamp-shade frames are 
mash-welded as shown in Fig. 235. Ordinary wire and sheet- 
metal oven gratings or racks, with seven cross-wires welded 
to the end pieces, have been made at the rate of 100 racks 
per hour, or 1,400 mash-welds. On certain kinds of wire work, 
it is desirable to butt-weld, and for this purpose the attach- 
ment shown in Fig. 236 is used. In general, however, where 
any amount of this kind of work is to be done, it is better 



288 



ELECTRIC WELDING 



to employ a regular butt-welding machine of the small pedestal 
or bench type. 

The spot-welding of galvanized ventilating pipe is shown 
in Fig. 237, and in Fig. 238 is shown the welding of 12 gage 
sheet steel machine guards. In this illustration the operator 
is using the foot-treadle which leaves his hands free to 
manipulate the work. In Fig. 239 the operator is welding 
gas-stove parts and the foot-treadle is thrown back out of the 




FIG. 239. Welding Stove Parts, Using a Swinging Bracket Support. 

way. A special bracket is employed to hold the work. The 
joints of this bracket are, ball-bearing, making it very easy 
to swing the work exactly where it is wanted to obtain the 
spot-welds. 

POINTS FOR SPOT WELDING 

The form of spot-welding points shown in Fig. 240, says 
A. A. Karcher, has been developed by the Challenge Machinery 
Co., Grand Rapids, Mich., with gratifying results. Fig. 241 
shows a typical weld and indicates the neatness, slight dis- 



S1'OT-\\I.;U)ING MACHINES AND WORK 



289 




Fill, ;:if,- FUUJI of 1*111111.-* IW Sjmt 





Ftfi. 24!.---Hjiit Wrhl Hiuiwiiiu Hli^ht I>inroltraficm and Freedom from i''Jm*h. 



290 



ELECTRIC WELDING 



coloration of the metal and entire freedom, from flash either 
on the outside or between the parts. In one view the dis- 
colorations give an erroneous impression of the existence of 
bosses on the face of the metal, which is actually flat except 
for the depressions at the points of the welds. 

The shape of the points would lead one to expect that the 
small projections would require a lot of attention to keep 
them in shape. Experience shows, however, that this is not 
the case, as the points actually lengthen slightly and occasion- 
ally have to be filed down. 

Even when a weld is made close to the edge the operation 
is quicker and consumes less current. A little practice in 
determining the correct amount of current to use is all there 
is to learn in handling these points. 

SIZES OF DIE-POINTS FOR LIGHT WORK 

The data on the size of die-points in Fig. 242 are given on 
the authority of Lucieii Haas, and may be considered good 




Rounded 




FIG. 242. Sizes of Die Points for Light Work. 

general practice. These points are intended for welding two 
pieces of the same gage and material. 

On certain kinds of heavy spot-welding work circular metal 
disks are placed between the plates in order to localize the 
current and to provide good contact. In other cases, projec- 
tions are made in one or both of the plates. These latter, 
of course, necessitate a mechanical or press operation, previous 



SPOT-WELDING MACHINES AND WORK 



291 



"Water Cooled 

Xlectcod* 




.Welding Prar 




,Watr-Cooled 
Hollow Electrode 



Steel Plunger 



Before Welding 



After Completion by Arc Welding, 
for Calking Purpose 




Gap 

Preaiut* Only 

lailda 



FIG. 243. The Tit or Projection Method of Welding. 




244. Winfield Sliding Horn Spot- Welding Machine. 



292 



ELECTRIC WELDING 




245. Winfield Heavy-Duty Machine with Adjustable Table. 




G. 246.- Winfield Portable Spot- Welding Machine. 



SPOT-WELDING MACHINES AND WORK 2 

to welding. Heavy plate work is shown in Fig. 243. At t 
upper left are shown plates as commonly arranged for weldir 
Next to this is a plate with a projection under the upper d 




FIG. 247. Winfield Portable Machine with Swivel Head. 

point. A steel plunger is used in the lower die to give th 
needed pressure after the metal is heated. This saves crushing 
or distorting the soft copper. In the lower right-hand corne: 



294 



ELECTRIC WELDING 




FIG. 248. Small Winfield Bench Machine. 




FIG. 249. Winfield Machine with Suspended Head for Welding 
Automobile Bodies. 



SPOT-WELDING MACHINES AND WORK 



299 



shown a ridge or tit weld, after the searn has been arc- 

Ided. 

The Winfield Machines. The machines made by the Win- 

d Electric "Welding Machine Co., Warren, Ohio, comprise 

r aried line for every conceivable spot-welding purpose. In 

leral, .Figs. 244 and 245 may be taken as typical of their 




FIG. 250. Convenient Setting of Machine for Sheet Metal Work. 

*ht and heavy spot-welding machines. Fig. 246 shows a 
try convenient form of portable machine. In Fig. 247 is 
own a much heavier portable machine with swiveling head, 
id in Fig. 248 is a small bench machine that is exceedingly 
jeful for light work. 



296 



ELECTRIC WELDING 
interesting machine is shown in Fig. 249. This 




251.-Pederal Welding Machine with Universal Points. 



This machine is in use in the plant of the Herbert Mann- 

fflftnrinff Co., Detroit. . 

Agood way to place a machine for some work as shown 
in Fig 250. This is employed in the shop of the Terrell 



SPOT-WELDING MACHINES AND WORK 



297 



Equipment Co., Grand Rapids, Mich., in the manufacture of 
steel lockers, steel furniture and the like. 

Federal Welding Machines. A feature of the spot-welding 
machines made by the Federal Machine and Welder Co., War- 
ren, Ohio, are the <f universal" welding points used on most 
of their output. The principle will be instantly grasped by 




Fro. 2fJ2. A Few Positions of the Universal Points. 



referring to Fig. 251. Some of the different positions possible 
are shown in Fig. 252. 

Another feature of these machines, is the use of the type 
of water-cooled points shown in Fig. 253. The welding point 
is copper and it is attached to the holder in such a way that 
the. water flows within half an inch of the actual welding 
contact. 



298 



ELECTRIC WELDING 



In, general form, size and capacities, the Federal line does 
not differ materially from the machines already shown. 




PIG. 253. Federal Water-Coolecl Points. 

FEDERAL ROTATABLE HEAD TWO-SPOT WELDING MACHINE 

The rotatable head two-spot, air operated welding machine, 
shown in Fig. 254, a 60-in. throat depth and is guaranteed 
to weld from two thicknesses of 24-gage up to two thicknesses 



SPOT-WELDING MACHINES AND WORK 



299 



of S-gage steel stock. Twelve welds per minute may be made 
in the latter size. 

The machine is built with a 4 kva. welding transformer 
in the upper and lower rotating heads. Primaries are in 
parallel while the secondaries are in series, so that two spot 
welds must be made at the same time. 

The welding electrodes or points arc 1-J in. in diameter, 
are carried in water-cooled holders, and are so arranged that 




FIG. 254. Federal Botatable Head Two-spot Welding Machine. 

welds from 3 to 8 in. apart may be made. The ends of each 
set of welding points can be separated a maximum of 5 in. 
The heads can be rotated through an angle of 90 deg. to permit 
welding at different angles on the stock being handled. 

Four air cylinders are used, each operating an independent 
point. The air control is hand operated and so arranged that 
an initial air line supply pressure of 80 Ib. will give from 
300 to 700 Ib. pressure between the points during the heating 
period. A second step on the air control makes it possible 



300 ELECTRIC WELDING 

to apply 1,200 Ib. pressure between the points for the final 
squeeze. The air is exhausted into the reverse side of the 
cylinders to withdraw the points. The regulating transformer 
supplies power to the welding transformer in eight voltage 
steps. 

FEDERAL AUTOMATIC SPOT-WELDER FOR CHANNELS 

The machine shown in Fig. 255 was made for spot-welding 
two rolled steel channels together to form an I-beani. It is 




FIG. 255. Federal Channel Welding Machine. 

capable of welding two spots at a time on two pieces of 
material % in. thick, at the rate of 60 welds per min. The 
two welding transformers are for 220 volts primary, and are 
air cooled. Four copper disks arc used for welding contacts. 
These are securely bolted to bronze shafts to insure good elec- 
trical connections. The secondaries of the welding trans- 
formers are connected to the brass bearings of these shafts, com- 
pleting the welding circuit. 

The welding current is controlled by auto transformers 



SPOT~\YKLIHN(J MAC-HLNKS AND WORK 301 

in the j)rimary circuit, in eight equal steps from 65 per cent, 
to full line volt-age. 

The welding disks can be adjusted to handle from 4 to 16 
in. channels. Simultaneous spot welds from 4 to 12 in. apart 
may be made. A variable speed motor is used to control the 
feeding of the work through the machine at from 25 to 60 
ft. per mill. 

AUTOMATIC PULLEY WELDING MACHINE 

The machine shown in Fig. 256 was made to weld the ring 
section of prcssed-metul pulleys, known as the filler, to the. 




Pl, Sirtl. A 



Ktt'Hrtr Pulley WiIlor. 



rim itself. This ring, or filler, not only nets as a Htififener 
for the rim, but is the part to which the outer ends oi* the 
spoken are attached. 

In welding, one-half of a pulley rim in locked by means 
oi a chain-clamping device in n rotating carrier, with the filler 
and spokes in place as shown. An adjustable mandrel on the 



302 



ELECTRIC WELDING 



carrier insures the proper distance between the center of the 
pulley and the rim face. Duplicate welding* sets operate on 
each side of the filler, and spot weld intermittently as the work 
is automatically indexed around. 

The mechanical part of the machine is motor driven, and 
with the work in place, the machine will properly space and 
weld around the filler until it reaches the end, when it auto- 
matically trips. The points are water cooled and will make 




PIG. 257. Taylor Cross-Current Spot- Welding Machine. 

about 60 welds per minute. These welding points can bo set 
to weld within 2-J in. of the center of the mandrel or supporting 
shaft, and have a maximum distance adjustment of 12 in. 
between them. The automatic indexing or feeding device is 
so arranged that welds from -J to 3 in. or more apart may 
be made. Pulleys from 12 in. up to 5 ft. in diameter may 
be handled, all the necessary adjustments being easily and 
quickly made to accommodate the various sizes, 



iYOKK 



This machine occupies a floor space of about MX 66 iu., 
weighs about )$,f>00 lb. 

The Taylor Welding Machines. \Yhile the machines made 

by the Taylor Welder Co., Warren, Ohio, differ radically from 
others oil the market, in that they employ double eleet rotles 
and cross current, the forms of the machines are about the 
same as those previously shown. An automatic belt-driven 
machine of the lighter type, is shown in Fijj;, 257. It may 




ftMtiv fttify \f iii-hiiir. 

'be operated by the foot- treadle also when drmretl. Thin 
machine has a rapacity up to two !/m, plates. The horns arc* 
water-cooled and the adjustable points nre locked in with a 
wrench as shown. FH*\ 2.*>* .shows a heavier typr of machine. 
This has a rapacity of two { in, plates; overhang is .'W in.; 
(listancr iictwci-n mpper bands and lou'er horn, (J in.; base, 
2<> -42 in.; cvtrrim- bi-iubl, 72 in.; greatest opening between 
welding points, .'! in.; wt'tidif abusit 2,-lHO Ib, The transformer 
is .'{."> kw. and then- is a ten strp sell' rontainrd rr^ulator for 



304 



ELECTRIC WELDING 



controlling the current. This firm makes other sizes and styles 
of machines, to meet all the demands of the trade. 

The general principle of the cross-current welding method 
employed in these machines is illustrated in Fig. 259. Two 
separate currents are caused to flow in a bias direction through 
the material to be welded. A high heat concentration is claimed 
for this method. In operation, the positives of two separate 



CROSS 



ENT 




SPO 



WEU5ING 



FlG. 259. Diagram of the Current Action in a Taylor Machine. 

welding currents are on one side of the material and the 
negatives on the other, with the co-working electrodes of each 
set so that the current travels diagonally across. An advantage 
claimed is that the electrodes on each side of the material 
may be set far enough apart to allow of the insertion of some 
hard material which will take the pressure instead of the. 
softer copper welding points. These hard dies may be operated 
independently of the copper ones and make it possible to weld 



KPOT-WKLDING MACHINES AND WORK 



heavier material without crushing the copper die points, as 
these need to be pressed together only enough to give good 




KM* LiOn. Autuumtii' 




Pill, *](H, ! 'nil ml tititf V**tt uf tf;j Ul 



co!tln't with I lie work, Tlie proreKH in alno nni(tle 
iu thai it can he o|M*ratt*<l with n intiltlptiiiHe elrcniit without 



306 ELECTRIC WELDING 

unbalancing the lines, which is not the case with any spot- 
welding machine employing a single current. 

Some Special Welding Machines. An automatic machine 
for forming and mash-welding 11 gage wire hog rings, at the 




.FiG. 262. Close-Up of Front of Hog-Ring Machine. 

tate of 60,000 per day, is shown in Fig. 260. This machine 
takes wire from two reels and turns out the complete hog 
rings. A partial rear view is shown in Fig. 261. A close-up 
of the front of the machine, with two hog rings lying on the 
platen, is given in Fig. 262. 



SPOT-WELDING MACHINES AND WORK 



307 



A machine in use in the punch press department of the 
General Electric Co., Schenectady, N. Y., is shown in Fig. 263. 
This machine welds small spacers to the iron laminations for 
motors and generators for ventilating purposes, and hence is 




FiG. 263. General Electric Space-Block Welding Machine. 

called a "space-block welder." A number of these machines 
arc in use in this plant, and they are capable of welding 60 
spots per minute when working continuously, not allowing for 
time to shift the stock. 

A combination spot- and line-welding machine, used in the 



308 



ELECTRIC WELDING 



General Electric Co.'s shops, is shown in Fig. 264. This is 
employed for welding oil switch boxes up to -J in. thick. As 
shown, the machine is fitted with a fixture for holding the 
boxes while line-welding the seams. A separate fixture is put 




FIG. 264. Combination Spot- and Lino-Welding Muc.hino, Set Up for 
Line- Welding Can Scams. 

on for spot-welding work. A seam 6 In. long can ho line- 
welded on this machine. 

Another combination machine, mod in the same shops, is 
shown in Fig. 265. This machine carries both tho spot- and 
the line-welding fixtures at th< k same time. Fig. 2CG shows 
the machine from the lino-welding side. As shown, tho 



SPOT-WELDING MAOHIXKS AM) WOHK 



309 



machines arc ready for welding straight plates. Machines of 
this kind should find a considerable field where it is desired 
to tuck seams before line welding them. These machines have 




'JIJ5.- -A <'tuiiltwtion M<him from tin 



a capacity of 20 Uva., and will weld tip to VMS in- thick, and 
seams 18 5n. long. 

Line welding machines, as developed in the Heheneotady 
plant, comprise* a transformer with a one turn secondary, 
through which a heavy current in delivered at low voltage to 
the material through the medium of a stationary jaw and roll- 



ELECTRIC WELDING 



ing wheel. Both the jaw and wheel are water-cooled and 
pressure is applied to the wheel the same as to a spot-welding 
tip. A small revolving switch mechanically geared to the 
driving motor and welding wheel operates a set of contactors 




PIG. 266. Machine from the Line- Wei ding Side. 

or solenoid switches to throw the power on once a second, the 
power being on f of a second, and off f of a second. The 
mechanism is synchronized so that during the f of a second 
the power is on, the welding wheel is rolling, and during the 



SPOT-WELDING MACHINES 'AND WORK 311 

mining of a second the wheel is stationary under pressure 
ile the soft metal is solidifying, thus completing the weld. 
Spot- Welding 1 Machines for Ship Work. During the World 
ir, welding of all kinds took huge steps forward. Spot- 
Lding developed at least as much as any other kind. Writing 
the General Electrical Revieiv, J. M. Weed says: 

The machines to be described are two portable welders, one with 12-in. 
?,h and the other with 27- in. reach, for use in the fabrication of 
ictural ship parts, and one stationary machine with 6-ft. reach designed 

welding two spots at the same time 011 large ship plates. 
A preliminary survey of the structural work in shipbuilding indicated 
t about 80 per cent of this work could be done by a machine of 12-in 
sh, and that a 27-in. reach would include the other 20 per cent. Since 
h the weight of the machine and the kva. required for its operation 

about 33 per cent greater for the 27-in. reach than for the 12-in. ; 
seemed advisable to develop two machines rather than one with the 
jjer reach. 

These machines were to a certain obvious extent patterned after the 
jting machines, which they were intended to replace as will be seen 
ai Fig. 267. They are necessarily considerably heavier than the riveting 
shines, but like these they arc provided with bales for crane suspension, 

the purpose of carrying the machines around the assembled work or 
ts to be welded. 

The maximum welding current available in these machines, with a steel 
te enclosed to the full deptn of the gap, is about 37,500 amperes, with 

maximum applied voltage of 534 volts at 60 cycles. Reduced voltages, 
ing smaller currents, are obtained in six equal steps, ranging from 

down to 267 volts, from the taps of the regulating transformers 
nished with the machines. 
This wide range of voltage and current was provided in order to meet 

possible requirements for a considerable range in thickness of work, 

for experimental purposes. Tests have shown, however, that the 

jhines will operate satisfactorily on work of thicknesses over the range 

which they arc likely to be used when connected directly on a 440-volt, 

sycle circuit, with no regulating transformers. Two plates A-in. thick 

welded together in spots from 1 in. to 1 in. in diameter, in from 
to 15 seconds. Thicker plates require more time and thinner plates 

time. 

The welding current under these conditions is about 31,000 amp.; the 
nary current is about 600 amp. for the. 12-in. machine and about 800 
r). for the 27-in. machine, the corresponding kva. at 440 volts, being 

and 350 respectively. 
Since the reactance of the welding circuit is large as compared with 

resistance, the voltage necessary for a given current, and eonse- 
ntly the kva. necessary for the operation of the machine, is 
tost proportional to the frequency. Thus, these machines operate satis- 



312 ELECTRIC WELDING 

factorily from a 25-cycle circuit at 220 volts, with the advantage that 
where the power-factor is from 30 to 40 per cent at 60 cycles, it is from 
60jto_75 per cent at 25 Cycles, and the kva. required at 25 cycles is about 
t 60 cycles. 



The maximum mechanical pressure on the work for which those machines 
are designed is 25,000 Ib. This is obtained from an 8-in. air cylinder, 
with an air pressure -of 100 Ib. per square inch, acting through a lever 
arm of 5 to 1 ratio. Lower pressures on the work are obtained with 




FIG. 267. Portable Spot-Welding Machine with 27-in. Throat Depth. 
Capable of Welding Two Plates f In. Thick in Spots 1 In. in Diameter. 
Made by the G-eneral Electric Co. 

correspondingly reduced air pressures. A pressure-reducing valve is pro- 
vided for this purpose, and also a pressure gage for indicating the pressure 
on the machine side of the valve. 

The pressure required to do satisfactory welding depends upon the 
thickness of the plates. It is necessary that the areas to be welded should 
at the start be brought into more intimato contact than the surrounding 
areas, in order that the current may be properly localized, and the heat 



SPOT- WELDING MACHINES AND WORK 313 

generated in the region where it is needed. It is therefore necessary, on 
account of irregularities in the plate surface, that the pressure should be 
great enough to spring the cold plate sufficiently to overcome the irregulari- 
ties. The pressure which will do this with heavy plates is ample for 
effecting the weld after the welding temperature is reached. 

It should be explained in this connection that the rate of heating at 
the surfaces to be welded depends largely upon the contact resistance, 
and consequently upon the condition of the plates and the pressure used. 
If the plates are clean and bright, and the pressure high, the rate of 
heating with a given amount of current is slow and the welding efficiency 
is poor. This makes it difficult to weld heavy plates if they are clean, 
since, as stated above, it is necessary to use large pressure with heavy 
plates to insure a. better contact of the areas to be welded than that of 
surrounding areas. It is. much easier to weld plates which carry the 
original coat of .mill, scale, or a fairly heavy coating .of . rust or dirt, 
affording a considerable, resistance which is not sensitive to pressure. If 
this resistance is too great, the necessary current will not flow, of course, 
but if the scale is not too heavy it. 1ms little effect upon the current, 
the high reactance of the welding circuit giving it practically a constant 
current characteristic and making the rate of heating proportional to the 
resistance within certain limits. The scale melts at about the welding 
temperature of the steel, and is squeezed out by the high pressures used, 
permitting the clean surfaces of the steel to come together and effect 
a good weld. 

A gage pressure of about 70 lb., giving 17,500 Ib. pressure upon the 
work, has been found to give good results under these conditions in Mn. 
plates. 

Both the mechanical pressure and the "current are transmitted to the 
work in these machines through heavy copper blocks or welding electrodes. 
The shape of the tips of these electrodes is that of a very flat truncated 
cone. 

The severity of the conditions to which the tips of the electrodes 
are subjected will be understood when it is considered that the current 
density in the electrode material tit this point is approximately 60,000 
JBlk..~ an< I- that this material is in contact with tne* steel 



plates which are brought to the welding temperature, under pressures of 
15,000 to 20,000 lb. per square inch. It must bo remembered, also, that 
copper, which is the best material available for this purpose, softens at 
a temperature considerably lower than the welding temperature of steel. 
The difficulty of making the electrode tips stand up under the conditions 
to which they are subjected has, in fact, constituted the most aerioua 
problem which has been met in the development of these machines. 

The shape of these electrodes gives them every possible advantage in 
freely conducting the current to and the heat away from the electrode 
tips, and in giving them the mechanical reinforcement of the cooler sur- 
rounding material. However, Jt has been found necessary to reduce, as 
far as possible, the heat generated at the tips of the electrodes by cleaning 
the rust and mill scale from the surfaces of the plates beneath the elee- 



314 ELECTRIC WELDING 

trodes. The most convenient way which has been found for doing this 
is by means of a sand blast. The bodies of the electrodes are also internally 
water-cooled by a stream of water flowing continually through them. Still, 
after all of these things have been done, a gradual deformation of the tip 
of the electrode will occur, increasing its area of contact with the work, 
and thus reducing the current density in the work and the pressure density 
below the values needed for welding. This would make it necessary to 
change electrodes and to reshape the tips very frequently, and the total 
life of the electrodes would be short on account of the frequent dress- 
ings. 

An effort has been made to overcome this difficulty by protecting the 
tip of the electrode by a thin copper cap, which may be quickly and 
cheaply replaced. As many as 160 welds have been made with a single 
copper cap, Yi 6 in. thick, before it became necessary to replace it. Un- 
fortunately this does not entirely prevent the deformation of the electrode 
tip, but it stands up much better than it does without the cap. 

Another method which has been tried for overcoming this trouble is 
by making the tip portion of the electrode removable, in the form of a 
disk or button, held in place by a clamp engaging in a neck or groove 
on the electrode body. While this protects the electrode body from 
deformation and wear, the tip itself does not stand up so well as does 
the combination of electrode and cap, where the tip of the electrode is 
not separated from the body. 

Some electrodes have been prepared which combine the features of 
the removable tip and cap. These give the advantage of a permanent 
electrode body, and the removable tip with the protecting cap stand up 
better than the unprotected tip. 

Some interesting features were introduced in the design of the trans- 
formers which are integral parts of these machines, owing to the necessity 
for small size and weight. Internal water cooling was adopted for the 
windings, which makes it possible to use current densities very much 
higher .than those found in ordinary power transformers. The conductor 
for the primary windings is f-in.x^-in. copper tubing, which was obtained 
in standard lengths and annealed before winding by passing it through 
an oven which is used for annealing sheathed wire during the process of 
drawing. "No difficulty was found in winding this tubing directly on the 
insulated core, the joints between lengths being made by brazing with 
silver solder. The entire winding consists of four layers of thirteen turns 
each in the 12-in. machine and three layers of thirteen turns each in the 
27-in. machine. 

The U-shaped single-turn secondaries were slipped over the outside of 
the primary windings in the assembly of the transformers. These were 
constructed of two copper plates each | in. thick and 6| in. wide, which 
were bent to the proper shape in the blacksmith shop, and assembled one 
inside the other with a ^-in. space between them. Narrow strips of copper 
were inserted between the plates along the edges, and the plates were 
brazed to these strips, thus making a water-tight chamber or passage for 
the circulation of the cooling water. 



SPOT-WELDING MACHINES AND WORK 315 

At 31,000 amp. the current density in these secondaries is about 6,200 
amp. per square inch, the" correspond ing densities in the primary windings 
being about 7,000 for the 12-in. and 9,000 for the 27-in. machine. 

In case these machines are started up without the cooling water having 
been turned on, the temperature rise in these windings will be rapid, and 
in order to avoid the danger of burning the insulation, asbestos and mica 
have been used. The copper tubing was taped with asbestos tape, and 
alternate layers of sheet asbestos and mica pads were used between layers 
of the primary winding, anil between primary and secondary and between 
primary and core. Space blocks of asbestos lumber, which is a compound 
of asbestos and Portland cement, were used at the ends of the core 
and at the ends of the winding layers. The complete transformer, after 
assembly, was impregnated with bakclitc. The result is a solid mechanical 
unit which will not be injured by temperatures not exceeding 150 deg. C. 
Several welds could be made without turning on the cooling water before 
this temperature would be reached. 

The transformers are mounted on a chamber in the body of the frame. 
The long end of the U-shaped secondary runs out along the arm of the 
frame and bolts directly to the copper base upon which the bottom electrode 
is mounted. The short end connects to the base of the top electrode 
through flexible leads of laminated copper, to permit of necessary motion 
for engaging* the work. 

The copper bases upon which the electrodes are mounted are insulated 
from the frame by a layer of mica, the bolts which hold them in place 
being also insulated by mica. 

The cooling water for these machines is divided into two parallel 
paths, one being through the primary winding, and the other through the 
secondary and the electrodes in scries. Separate valves are supplied for 
independent adjustment of the flow in the two paths. The resistance of 
ordinary hydrant water is sufficiently great as to cause no concern regarding 
the grounding or short-circuiting of the windings through tho cooling water, 
although it is necessary to use rubber tubing or hose for leading it in 
and out. 

Some pieces of ly^2-in. machine steel were welded in seven seconds 
with a current of 33,000 amp. They were afterward clamped in a vise 
and hammered into U-shapes. Small pieces were sheared from the searn 
where two -J-in. plates had been welded together in a row of spots. The 
pieces of the plates were then split apart with a cold diigjol in one case, 
and an effort was made to do so in the other, with the result that one 
piece of plate broke at the welds before the welds would themselves break. 
Such tests as these show that the welds are at least as strong as the 
material on which the welds were made. Some samples of the Jx^-in. 
stock welded together in the same manner were tested by bending in an 
edgewise direction, thus subjecting the welds to a shearing torque. The 
ultimate strength calculated from these tests was in the neighborhood of 
65,000 Ib. per square inch. These tests showed also a very tough weld, 
tho deflection being almost 45 deg. in some cases before the final rupture 
occurred. The maximum load occurred with a deflection of from 3 to 5 



316 



ELECTRIC WELDING 



cleg, with a very gradual reduction in the load from this time till the 
final rupture. 

The Duplex Welding Machine. The machine shown in Pig. 268 was 
developed for the application of electric welding as a substitute for riveting 
on parts of the ship composed of large-sized plates, which may be fabricated 
before they are assembled in the ship. The specification to which it was 
built stated that it should have a 6-ft. reach and should be capable of 
welding together two plates J in. thick in two spots at the same time. 
A machine capable of doing this work, with a 6-ft. gap, is necessarily 




268. Duplex Spot- Welding Machine. Made by the General Electric 
Co. 6-ft. Throat Depth, and Capable of Welding Together Two Steel 
Plates | In. Thick, in Two Spots 1| In. in Diameter. 



so heavy as to preclude even semi-portability, and no effort was made in 
this direction. 

With the welding circuit enclosing a 6-ft. gap, and carrying the very 
heavy current necessary to weld |-in. plates, the kva. required would be 
very large. A great reduction in the kva. and at the same time a doubling 
of the work done, is obtained in this machine by the use of two trans- 
formers as integral parts of the machine, and two pairs of electrodes, 
thus providing for the welding of two spots at the same time. The 
transformers are mounted in the frame of the machine, on opposite sides 
of the work, and as near to the welding electrodes as possible, so as to 



SPOT-WELDING MACHINES AND WORK 317 

obtain the minimum reactance in the welding circuit. The polarity of 
the electrodes on one side of the work is the reverse of that of the opposed 
electrodes, thus giving a series arrangement of the transformer secondaries, 
the current from each transformer flowing through both of the spots to 
be welded. 

The bottom electrodes are stationary, and the copper bases which bear 
them are connected rigidly to the terminals of their transformer, while 
the bases which carry the top electrodes are connected through flexible 
leads of laminated copper, to permit of the motion necessary for engaging 
the work. 

Previous tests with an experimental machine had shown that, to suc- 
cessfully weld two spots at the same time in the manner adopted here, 
it is necessary that the pressures shall be independently applied. Otherwise, 
due to inequalities in the thickness of the work, or in the wear and tear 
of the electrodes, the pressure may be much greater on one of the spots 
than on the other. This results in unequal heating in the two spots. The 
resistance and its heating effect are less in the spot with the greater 
pressure. The two top electrodes in this machine were therefore mounted 
on separate plungers, operated by separate pistons through independent 
levers. 

The pressures obtained in this machine with an air pressure of 100 
Ib. per square inch, are 30,000 Ib. on each spot, giving a total pressure 
of 60,000 Ib. which must be exerted by the frame around the 6-ft. gap. 
The necessary strength is obtained by constructing the frame of two steel 
plates, each 2 in. thick, properly spaced and rigidly bolted together. 

The use of steel in this case is easily permissible on account of the 
restricted area of the welding circuit and its relative position, resulting 
in small tendency for magnetic flux to enter the frame. However, the 
heads carrying the electrodes, being in close proximity to the welding 
circuit, were made of gun metal. 

The two air cylinders are mounted on a cast-iron bed-plate in the 
back part of the machine. The levers connecting the pistons to the electrode 
plungers, which are 7 ft. in length, were made of cast steel, in order to 
obtain the necessary strength. 

The maximum welding current for which this machine was designed is 
50,000 amp. This current is obtained with 500 volts at 60 cycles applied. 

The distance between the electrode bodies for this machine is fixed 
at 8 in., center to center, but the distances between the centers of the 
tips may be easily varied from 6 in. to 10 in. by shifting the tip from 
the center of the body toward one side or the other. 

Provision has been made for shifting the electrodes on their bases to 
positions 90 deg. from those shown in the picture, thus -spacing the welds 
in a direction along the axis of the machine instead of traverse to it. 

. The transformers are insulated and cooled in the same manner as 
those in "the semi-portable machines. The windings are interlaced in order 
to obtain minimum reactance, the primary being wound in two layers of 
14 turns each, one inside and the other outside of the single turn secondary. 

With 50,000 amp. in the secondaries of these transformers, the current 



318 



ELECTRIC WELDING 



in the primary is 1,800. The respective current densities are 7,000 and 
9,000 amp. per square inch. The kva. entering the transformers on this 
basis, the two primaries being in series on 500 volts, is 450 for each 
transformer. 

This machine also has been provided with a regulating transformer 
for applying different voltages to give different values of welding current, 




FIG. 269. General Electric Co.'s Experimental Hpot-Welding Machine. 
Current Capacity 100,000 Amp. Pressure Capacity 3(3 Tons, lias 
Welded Three Plates, Each 1 In. Thick. 

and with a panel carrying the necessary selector switches and contactor. 
The maximum voltage provided by this regulating transformer as at 
present constructed is 440. If it is found that tho current obtained with 
this voltage is not sufficient for the heaviest work which it is desired to 
do with this machine, the maximum voltage may be changed to 500. 

Tho kva. entering the transformers of 440 volts will be approximately 
350 each, instead of 450. 



SPOT-WELDING MACHINES AND WORK 



319 



In order that this machine may be operated from any ordinary power 
circuit, it will be necessary to use a motor-generator set provided with 
a suitable flywheel. This will eliminate the bad power-factor, distribute 
the load equally on the three phases, and over a much larger interval of 
time for each weld, thus substituting small gradual changes in power for 
large and sudden changes. On account of the high reactance the welding 
current will remain practically Constant as the speed of the motor-generator 
set falls away, thus favoring the utilization of the flywheel. The total 
maximum power drawn from the circuit with this arrangement would be 
about 100 kilowatts. 




FlG. 270. Portable Machine for Mash-Welding Square or Round Rods. 

A Heavy Experimental Spot- Welding Machine. The 

machine shown in Fig. 269 was built in 1918 by the General 
Electric Co., in order to investigate the possibilities of welding 
plates from J in. up. Three plates each 1 in. thick have been 
welded with it. The machine is provided with a 2,000-kva. 
transformer, having a capacity of 100,000 amp. at 20 volts. 
Hydraulic pressures up to 36 tons are obtained at the elec- 
trodes. Motor-generator sets of 500- and 6,000-kva. capacity 



320 



ELECTRIC WELDING 



were used. Prom the nature of the service, it was apparent 
that some form of cooling was needed at the contact points. 
It was found, however, that it was impossible to water-cool 
the points sufficiently to give a reasonable life to the electrodes 
if they were kept the same diameter for any distance from 
the work. In consequence heavy masses of copper were placed 




PIG. 271. Lorain Machine for Spot- Welding Electric, Rail Bonds. 

as close to the points of contact as practicable. By doing this 
it was possible to have a very large cooling surface at the 
top of the electrode and by passing water through this part 
at the time of welding and between welds, the joints were kept 
cool enough for all practical purposes. 

A portable machine for making mash-welds for splicing or 
attaching round or square rods cross-wise, is shown in Fig. 



SPOT-WELDING MACHINES AND WORK 321 

270. This was made by the General Electric Co., for ship- 
yard use. 

A big machine for spot-welding electric railway bonds, is 
shown in Fig. 271. This is made by the Lorain' Steel Co., 
Johnstown, Pa. It will weld two plates 18 in. long and 3 in. 
wide by 1 in. thick, each plate having three raised ''welding 
bosses. ' ' Pressure as high as 35 tons is obtainable and current 
up to 25,000 amp. may be used. 

Spot- Welding Data. It is difficult to give definite costs for 
spot welding, as much depends on the operator. A careless 
or inexperienced operator will waste more current than a good 
one, and various conditions of the metal being worked on 
will make a considerable difference at times. However, the 
information given in Table XXIII, which is furnished by the 
Winfield Electric Welding Machine Co., will prove of value 
as a basis for calculations. Tables XXIV and XXV will also 
be useful to use in connection with the measurement of the 
thickness of sheets, and in comparing different gages. 

TABLE XXIII. SPOT-WELDING POWER AND COST DATA 



Thieknoss of 
Gauge Sheets in 
Number Fractions of 
an Inch 


Thickness of 
Sheets in 
Decimals of 
an Inch 


K. W. 
Required 


H. P. 
Required 


Time in 
Seconds 
to Make 
a Weld 


Cost 1000 
Welds at one 
Cent per 
K. W. Hour 


30 


VBO 


.0125 


3.0 


4.2 


.25 


.002 


28 


v 


.0156 


4.0 


5.6 


.3 


.003 


24 


740 


.0250 


5.0 


7.0 


.45 


.006 


20 


- Vso 


.0375 


6.5 


9.2 


.6 


.011 


18 


7=o 


.0500 


8.0 


11.3 


.8 


.017 


16 


Vi. 


.0626 


9.5 


13.5 


1.0 


.026 


14 


'/ 


.0781 


10.0 


14.2 


1.3 


.036 


12 


V 


.1093 


12.0 


17.0 


1.6 


.052 


11 


7s 


.1250 


13.0 


18.5 


1.7 


.061 


10 


V 


.1406 


14.0 


19.9 


1.8 


.070 


9 


R / 

/33 


.1562 


15.0 


21.3 


1.9 


.079 


8 


"/ 


.1715 


16.0 


22.7 


2.0 


.088 


7 


V 


.1875 


17.0 


24.1 


2.1 


.099 


6 


'% 


.2031 


18.0 


25.6 


2.2 


.110 


5 


v 


.2187 


19.0 


27.0 


2.4 


.124 


4 


'% 


.2343 


20.0 


28.4 


2.7 


.148 


3 


'A 


.2500 


21.0 


29.8 


3.0 


.174 



As the cost of current varies in different places, we have figured the 
current at one cent per K. W. hour to give a basis for calculating the 
cost. Multiply the cost of current given above by the rate per K. W. hour 
you pay and you will have your cost per 1000 welds for current. 



322 



ELECTRIC WELDING 



H 

CQ 
03 



4* 
K 

I 



K 
W 
<72 

fc 
O 



O 



^ 



M 

2 





s 




a as 

cua < 



f!t 

B fi < 



.0 fcC 

a * 

9 r ta 



o 1 
CO 



1 

ll 



SO; 

=> r 
55 ^ 



i o 5 



l> GO D S* 00 i -! t* CO CO G* Ift 



1 1 I 1 1 

t -,O5*O-<CO 



O O 

o 



O 1C 
-^ CO O t- 



to oo - 
rH I-H r- -4 r-4 ^H oi <si i oi co 



10 t 00 rH 10 00 r-< "* l> GO 
^r-FHG*Q*G*<SOCO 

oooooooooo 



o ooo o o o o GO 
JL IT- ?T?TT?? 17^777' 



000*0*0*0*0*0*0*0*0*0*1 



SPOT-WELDING MACHINES AND WORK 



323 



TABLE XXV. DECIMAL EQUIVALENTS OF AN INCH FOR MILLIMETERS, 
B. & S. AND BIRMINGHAM WIRE GAGES 



Decimal 
Inch 


Mill. 


Fra. 
In. 


B&S 


Birm 
Gge. 


Decimal 
Inch 


Mill. 


Fra. 
In. 


B&S 


Birni 
Gge. 


Decimal 
Inch 


Mill. 


Fra. 
In. 


B&S 


Birrn 
Gge. 


.00394 
.00787 
.010025 


.1 
.2 




30 




. 11443 
.11811 
.12 


3.0 




9 


11 


.296875 
.29921 
.3 


7.6 









.011257 






29 




. 12204 


3.1 








30314 


7.7 








.01181 


.3 








.125 




Js 






. 30708 


7. '8 








.012 








30 


. 12598 


3.2 








.31102 


7.9 








.012641 






28 




. 12849 






S 




.3125 




,s- 






.013 








29 


. 12992 


3.3 








! 31496 


8.0 


16 






.014 








28 


. 13385 


3.4 








.31889 


8. 1 








.014195 






27 




.134 








10 


32283 


8^2 








.015625 




& 






. 13779 


3.5 








.32495 






o 




.01575 


.4 








. 140625 




A 






.32677 


8.3 








.01594 






26 




. 14173 


3.6 








.328125 




li 






.016 








27 


. 14428 






7 




.3307 


8.4 








.0179 






25 




. 14566 


3.7 








. 33464 


8.5 








.018 








26 


.148 








9 


.33858 


8.6 








.01968 


.5 








. 14960 


3.8 








.34 








o 


.02 








25 


. 15354 


3.9 








.34251 


8.7 








.0201 






24 




. 15625 




h 






. 34375 




& 






.022 








24 


. 15748 


4.0 








. 34645 


8 8 








.022571 






23 




.16141 


4.1 








. 35039 


8.9 








. 02362 


.6 








. 16202 






6 




. 35433 


9.0 








.025 








23 


.165 








8 


. 35826 


9. 1 








.025347 






22 




. 16535 


4.2 








. 359375 




$f 






. 02756 


.7 








. 16929 


4.3 








.36220 


9.2 








.028 








22 


. 171 875 




tt 






.3648 








00 


. 02846 






21 




. 17322 


4.4 








.36614 


9.3 








.03125 




h 






. 17716 


4.5 








.37007 


9.4 








.03149 


.8 








.180 








7 


.37401 


9.5 








.03196 






20 




.1811 


4.6 








.375 




5-8 






.032 








21 


. 18194 






5 




.37795 


9.6 








.035 








20 


. 18503 


4.7 








.38 








00 


. 03543 


.9 








. 1875 




A 






.38188 


9.7 








. 035S9 






19 




. 18897 


4.S 








.38582 


9.8 








. 03937 


1.0 








.19291 


4.9 








.38976 


9.9 








. 04030 






18 




. 19685 


.0 








.390625 




H 






.042 








19 


. 20078 


.1 








.3937 


10.0 








.0433 


1.1 








.203 








6 


.39763 


10.1 








. 04525 






17 




.203125 




if 






.40157 


10.2 








. 46875 




& 






.20431 






4 




.40551 


10.3 








. 04724 


1.2 








. 20472 


.2 








.40625 




il 






.049 








IS 


. 20806 


.3 








.40499 


10.4 








. 05082 






16 




.21259 


j.4 








.4096 






000 




,05118 


1.3 








.21053 










.41338 


10.5 








.05512 


1.4 








.21875 




& 






.41732 


10.6 








. 05706 






15 




.22 








5 


.42125 


10.7 








.058 








17 


. 22047 


.6 








.421875 




2 






. 05905 


1 r t 








. 2244 


.7 








.425 








000 


. 0625 




fa 






. 22S34 


,S 








.42519 


10.8 








. 06299 


1.6 








. 22042 






3 




.42913 


10.9 








. 06408 






14 




. 23228 


5.9 








.43307 


11.0 








.065 








16 


. 234375 




tt 






.437 


11.1 








.06692 


1.7 








. 23022 


6.0 








.4375 




A 






. 07086 


1.8 








.238 








4 


. 44094 


11.2 








.07196 






13 




.24015 


6.1 








.44488 


11.3 








.072 








15 


. 24409 


6.2 








.44881 


11.4 








.0748 


1.9 








. 24803 


6.3 








.45275 


11.5 








. 078125 




& 






.25 




K 






.453125 




II 






. 07874 


2.0 








.25196 


0.4 








.454 








0000 


.080801 






12 




. 2559 


6.5 








. 45669 


11.6 








. 08267 


2.1 








. J5763 






2 




.46 






0000 




.083 








14 


. 259 








3 


.46062 


11.7 








. 08661 


2.2 








. 259,84 


0.6 








.46456 


11.8 








. 09055 


2.3 








. 26377 


6.7 








.4685 


11.9 








. 09074 






11 




. 265625 




tt 






.46875 




M 






. 09375 




& 






.26771 


0.8 








.47244 


12.0 








. 09448 


2.4 








.27165 


6.9 








.47637 


12.1 








.095 








13 


. 27559 


7.0 








.48031 


12.2 








. 09842 


2.5 








.27952 


7.1 








.48425 


12.3 








. 10189 






10 




. 28125 




A 






. 484375 




tt 






. 10236 


2.6 








. 28346 


7.2 








.48818 


12.4 








.30629 


2.7 








.284 








2 


.49212 


12.5 








.109 








12 


.2874 


7.3 








.49606 


12.6 








. 109375 




& 






.2893 






1 




.49999 


12.7 








. 11023 


2.8 








.29133 


7.4 








.5 




Vi 






.11417 


2.9 








. 29527 


7.5 








. 50393 


12.8 









CHAPTER XIV 

WELDING BOILER TUBES BY THE ELECTRIC 
RESISTANCE PROCESS 

About 1912 the resistance, or Thomson, process of electric 
welding was first tried out in a locomotive shop for the purpose 
of replacing the oil-furnace welding equipment in safe-ending 
boiler tubes up to 2^ in. in diameter, says P. T. Van Bibber, 
in the American Machinist. At the present time, in shops in 
different parts of the country where electric welding machines 
have been installed, one will find many enthusiastic " boosters " 
for this process. It is to these users that we are indebted for 
the information contained in this article and for the benefit 
of those who are unfamiliar with this adaptation of resistance 
welding, an endeavor has been made to cover all the details 
possible. 

In using the resistance type of machine for welding safe- 
ends onto locomotive-boiler flues, the old tube and the new 
safe-end are gripped securely in heavy copper jaws with the 
ends to be joined held in alignment. As these ends are 
pressed together a large volume of current from the secondary 
winding of the transformer is passed through them. Since the 
junction of the abutting ends is the point of greatest resistance 
to the electric current, the greatest heating effect is there 
and, usually, on a 2|-in. tube it requires only about 15 see- 
to secure a perfect running or welding heat. A slight push-up 
by the pressure device on the welding machine sticks the two 
parts together solidly enough so that the tube can be removed 
to the mandrel of a rolling machine, exactly as is done when 
welding by the oil-furnace method, and the weld is then com- 
pleted in a few seconds by rolling down the joint. 

Since it is always necessary to scarf the ends of a tube 
and new safe-end before welding by the oil-furnace 
method, the first question that the practical boiler-shop man 

324 



WELDING BOILER TUBES 



325 



.1 ask is, How much preparation is needed for electric resist- 
3e welding 1 ? The first step in any method is to clear the 
>e from heavy scale, if in use under bad water conditions, 
rolling in a large tumbling barrel. After this, the tubes 
5 cut to the desired length to remove the old end that is 
be replaced by the new section. 

In some shops it is the practice to never allow more than 
3 or two welds in a tube, which means that after removing 
i second time, the tiibe must be used in a shorter boiler than 
:ore. This procedure is carried out until the tube can only 




FIG. 272. Machine for Cutting Off Flues. 

used for small switching locomotives if it lasts that long 
ifter which it is scrapped. By this method, only one length 
tube is bought new, which is that required for the longest 
tiers. 

In other shops the writer found tubes with many welds, 
>wing that the safe-ending was continued in order to main- 
n the same length each time until the tube was worn out, 
ten it was replaced by a new one of the required length, 
is latter method necessitates buying several lengths new 
t in localities where the water is not very hard on tubes, 
prevents a tube from going to the scrap pile as long as there 



326 



ELECTRIC WELDING 



is any good in it. After cutting off the old tubes, as shown 
in Fig. 272, which represents a common type of machine for 
this purpose, the tubes are next scarfed, or cut off square, 
according to which method of welding is to be employed. 
If a scarf weld is to be used, the old tube is generally 



Old Tube 



7/////////////////////////S 



Hew End 



FIG. 273. Ends Prepared i'or Scarf- Weld. 




FIG. 274. Bolt Threading Machine Made Into a Scarfing Machine. 

beveled on the outside at an angle of from 45 to 60 deg. 7 
according to the length of scarf desired, about as shown in 
Fig. 273. The bevel is wholly a matter of personal opinion 
for just as good welds can be made with a 30-deg. scarf as 
when one of 60 deg. is used. 



WELDING BOILER TUBES 



One type of machine used for scarfing is shown in Fig. 274. 
This has been rigged up from an old bolt-threading machine. 
The jaws shown at the left are for gripping the old tube which 
is then fed into a revolving chuck by means of the handwheel. 
This chuck contains the necessary cutters for forming the 
desired bevel on the outside of the tube end. The jaws on 
the right-haud side of the same machine grip the new short- 
ends as they are fed onto a revolving tapered reamer, which 
cuts a scarf from the inside. In some shops, the scarfing is 
done on an old lathe with special fixtures, but the remodeled 
bolt-threading machine seems to offer the most efficient proposi- 
tion for, with this type of machine, it is possible for one man 
to scarf over 60 tubes and ends per hour. 



Old Tube 



New End 



FIG. 275. Ends Prepared for a Straight Butt-Weld. 

If a straight butt-weld is to be made instead of scarfing 
the ends to bo joined, they are cut off squarely, as shown 
in Fig. 275. This is done in an old pipe-threading machine, 
or a lathe, so that when placed in the welding machine, the 
abutting ends will be in contact practically all the way around 
their circumference 1 . Although this last method of preparing 
work may sound shorter than scarfing, nevertheless, from actual 
observation of both methods in different shops, the former is 
faster by nearly two to one. 

After preparing the ends for welding, if the tubes have 
not already been tumbled to remove all scale, which usually 
leaves the outside surface quite bright and clean, it is necessary 
to grind the surface of both old tube and new ends back to 
a distance of about 8 in. in order to secure a good electrical 



328 ELECTRIC WELDING 

contact between the tube metal and the copper jaws of the 
welding machine. 

There are three distinct methods of welding boiler tubes, 
which are called butt-, scarf- and flash-welding, the latter 
producing the same effect as a scarfed joint when completed. 
In the straight butt-weld, the ends to be joined are first brought 
firmly together by means of the pressure device on the w r elding 
machine, and the current is then turned on. There is always 
some point around the circumference of the tube which starts 
to heat first, due to the impossibility of making the two ends 
to abut with the same pressure at all points of their contacting 
surfaces. However, the heat will gradually become uniform 
all around the circumference before the welding temperature 
is reached. The current is maintained through the tubes until 
the joint reaches a good running heat, as evidenced by a 
" greasy " appearance of the surface, when the pressure is 
applied sufficiently to push up the hot metal about -J- in. which 
partly completes the weld. The jaws are then released and 
the tube is immediately thrust onto the mandrel of the rolling 
apparatus, which is described further on, and the bulge at 
the joint, caused by the pushing up of the hot metal, is rolled 
down until the joint is of the same diameter as the original 
tube. 

This rolling-down operation, in addition to reducing this 
bulge of the tube, also forces a complete union of the plastic 
metal of the two pieces, thereby completing the weld. From 
this it may be seen that in welding boiler tubes, the welding 
machine is only used for a heating device to supplant the oil 
furnace, requiring only sufficient pressure to stick the ends 
together to hold it while removing work to the rolling machine 
where the welding is finished. 

In the scarf weld, the beveled end of the old tube is pushed 
into the chamfered end of the new piece and the current then 
turned on the same as in making the butt-weld just described. 
Due to the "feather" edge of the short new piece, it is often 
necessary to apply the current intermittently until the joint 
is well heated all around the circumference ; otherwise points 
of the sharp edge, which come in contact first with the opposite 
member, will be burned off before the heat is evenly distributed 
around the tube. Owing to the expanding effect of the scarfed 



WELDING BOILER TUBES 



329 



ids, it is not necessary to apply so much pressure as with 
ie butt-weld when the metal is plastic in order to stick the 
.eces together before rolling down. 

With either of the above welds, it is necessary to give the 
d tube more projection beyond the copper clamping jaws 
tan is given the new short piece. This is because the wall 
dckncss of the old tube has been slightly reduced by wearing 
vay in service and if the two parts were given the same 
ejection, the end of old tube would heat much more rapidly 
ian that of the new piece since its resistance to the electric 
irrent would be greater, owing to the reduced sectional area, 
is always necessary for the heat to form uniformly in each 



Old Tube 



New End 



FIG. 276. Ends Prepared for a Flush-Weld. 

: the abutting ends or one will burn away before the other 
aches the plastic stage. 

In making a flash- weld, not so much preparation is required 
i for the two other methods just described; hence it is a 
uch cheaper job and yet, from all tests made so far, it is 
.e only type of joint which is always 100 per cent perfect 
hen considering the number of defective- welds in any lot 
: tubes. The old tube is cut off the right length in a machine, 
Inch has a cutting wheel so beveled as to give an angle of 
) deg. from the vertical on the end of the tube, as shown in 
ig. 276. The new ends are bought direct from the tube 
anufacturers with both ends cut square and the surface 
eaned well so that there is no preparation needed on the 
jw pieces. After cutting off the old tube it is only necessary 

grind it en the outside about 8 in. back from the end to 
sure good electrical contact. The old tube is placed in the 



330 ELECTRIC WELDING 

clamps with about 4 in. of projection and the new end with 
about 3 in. The current is turned on first and the pressure 
is then applied very slowly and steadily to bring the abutting 
ends into contact. As soon as they meet, a small arc or "flash" 
is formed which commences to burn away the points of metal 
coming into contact first. This flashing is continued until the 
abutting ends are arcing all the way around the circumference 
and by this time the sharp edge of the old tube, although 
somewhat burned away itself, has burned its way into the 
square-cut end of the new piece. A sudden application of more 
pressure stops the flashing and the joint then quickly attains 
the running or welding heat as in the butt- or scarf -welding 
method. The ends are now shoved together and as the current 
is turned off, the end of the old tube will have forced itself 
into the end of the new piece sufficiently to form a scarf-weld 
when rolled clown in the rolling machine. 

Using a Flux. From statements made by every operator 
interviewed, the use of flux does not help the welding in any 
way; yet it is used in each shop because it clears up the 
surface of the metal when the plastic stage is reached and 
enables the operator to judge the appearance of the heat more 
easily. The writer is confident that if a new operator were 
to be broken in on a welding machine, he would soon be able 
to correctly judge the right welding heat of the metal by its 
appearance without any flux, as there are many pipe shops 
using electric-welding machines for making joints in long coils, 
where flux was never heard of. Each railroad shop uses a 
slightly different kind of flux, but .generally this material is 
nothing more than a common yellow clay, streaked with quartz 
formation, which has been pulverized and thoroughly dried 
out before using. 

There are several methods and machines employed in the 
various shops for rolling down and completing the weld after 
heating the joint properly. One of the simplest machines in 
use is shown in Fig. 277. It consists of a power-driven mandrel 
slightly smaller than the internal tube diameter, above which 
is a power-driven roller. This roller is held a short distance 
above the mandrel by a spring. When the hot tube is thrust 
onto the mandrel, the upper roller is brought firmly down onto 
the outside surface of the joint by pressure on a foot treadle 



WELDING BOILER TUBES 331 

located under the table on which the device is mounted. The 
pressure is maintained until the joint has been rolled down 
to outer tube size. The main disadvantage of this style of 
apparatus is that the speeds of the roller and the mandrel must 
be in the correct ratio so as to not allow any slip on either 
inner or outer surface of the tube, otherwise the tube will roll 
unevenly and when finished will have a thicker wall on one 
side than on the other. However, this is the earliest form of 
rolling machine used with the electric-welding method and 




FIG. 277. Simplest Form of Boiling Machine. 

is still giving fairly satisfactory service in two well-known 
shops today. 

Another type, which is more elaborate but more positive, 
is a three-roller machine, shown in Fig. 278. The mandrel 
here is stationary and the three idling rollers, being mounted 
on a power-driven head, continually revolve around it. After 
inserting the tube, which is also held stationary, pressure is 
applied by means of a hand lever which closes the three rollers 
in toward the center of the mandrel and the joint is rolled 
down by the surface pressure of the three rollers revolving 
around it. In order to still further insure uniform rolling, 
the tube is turned slightly on the mandrel three or four times 



332 



ELECTRIC WELDING 



during the rolling operation since the mandrel is slightly 
smaller than the tube and if the latter were to be held in only 
one position, a difference in wall thickness on one side might 
result- 
Rolling machines of the types just described are sometimes 
located in direct alignment with the jaws of the welding 
machine, so that after obtaining the proper heat, it is only 
necessary to release the jaws and shove the hot tube directly 




PIG. 278. The Three-Boiler, or Hartz Type, Machine. 

onto the mandrel. If the three-roller type is being used, the 
tube is held stationary by locking one jaw of the welding 
machine. When a new position on the mandrel is desired the 
jaws are released and the tube allowed to turn slightly with 
the friction of the revolving rollers. 

Another method is to have the rolling machine in back of 
the welding machine so that when the correct heat is obtained 
the tube is lifted out of the jaws by the operator's assistant 



WKUMNIJ BOILER TUBES 333 

who shovrs it onto the rolling mandrel, leaving the operator 
free 1o get the next lube lined up in the machine for heating, 
lu this last method, the assistant must act quickly so as not 
to allow the joint to cool down before the rolling, as he cannot 
transfer the tube from the welding to the rolling machine as 
quickly as the operator could shove it forward onto the mandrel 
as first mentioned. 

As to speed in welding, the writer observed that the, same 
production could be obtained in different shops by either 
method of locating the rolling machine; hence it is purely a. 
matter of space available around the welding machine, and 
local opinion, 

A third way of handling the rolling down is to have the 
rolling machine built onto the 'welding machine, as shown in 
Fig. 27!). In this particular apparatus, the mandrel is made 
long enough to permit welding in to a distance of 10 ft, from 
the joint, so as to reclaim old short tubes by making a new 
long one with a joint in the middle. This reclaiming of tubes 
has proved to be perfectly practical, having been forced in 
one locomotive shop during the war due to the inability to 
obtain new tube stock. Tin* mandrel is power driven as well 
as the upper roller, while the two lower rollers are idlers. 
After obtaining the welding heat, it is only necessary to move 
the tube about one foot to bring the joint onto UK- rollers. 
A clutch at the rear end is then thrown in to revolve the 
mandrel and upper roller, and pressure is applied through tin 1 
latter by means of an air cylinder mounted above it. While 
being rolled the tube is allowed to revolve freely in the open 
jaws of the welding machine. The rear end of the tube is 
supported on idling rollers. 

After the rolling-down process, which is the same as has 
always been used with the oil-furnace method of welding, the 
tubes are subjected to the annealing and end-swaging processes. 
They are then usually tested hydrostatieally for possible leaks 
and stacked away ready for assembling in the boiler. The 
percentage of leaks is less than f> per cent in any shop, and 
in one shop they are so sure of their welding that the tubes 
are not tested until completely assembled in the boiler when 
the fatter is subjected to a hydrostatic test as a complete unit. 
This particular shop ti,:es the flash-weld method and has never 



334 



ELECTRIC WELDING 




WELDING BOILER TUBES 335 

had a defective joint since the welding machine was installed 
over four years ago. 

Merits of Electric and Oil Heating. When asked to com- 
pare the electric welding with the oil-furnace method on boiler 
tubes of any size, one of the oldest users of the former replied 
that there was "no comparison. " Using oil it was never 
possible to average over 30 or 40 welds per hour on tubes 
up to 3 in. with one furnace and one gang. This meant that 
the tube shop was always behind the rest of the repair depart- 
ments and working overtime a great deal in order to catch up. 
Fuel oil will vary greatly in different lots as well as under 
different atmospheric conditions, so the oil furnace itself is 
a constant source of aggravation and calls for continual adjust- 
ing, which means an interruption in production while the fire 
is regulated. 

As to production, with an electric-welding machine, the 
average output on tubes up to 3 in. in diameter, taken from 
all shops using this process, will run 60 completed welds per 
hour, requiring one operator and a helper at the machine and 
a third man to prepare the work for welding. In the days 
of piecework, in some of the shops, records show that the 
maximum number of small tubes turned out in any shop, 
with the same number of men, was 125 per hour or a little 
better than one tube -every 30 sec. and this could be kept up 
for two hours at a time without greatly tiring the men. This 
speed was obtained by three different shops, each using a 
different style and arrangement of rolling-down apparatus, 
which shows that all of the methods outlined previously in this 
article are equally fast. 

On welding superheater tubes at the reduced section, where 
the diameter at the point of weld is about 4$ in., the production 
will run about 10 to 20 welds per hour, although better time 
has been made on. piecework. By comparing these figures with 
the oil-furnace welding production, even under the best of 
working conditions, nothing further need be said as to the 
speed of the electric process. 

As to cost, there are no figures available later than 1916, 
which of course would be much lower than at the present day, 
but by comparing costs of both methods at that time, taking 
into consideration upkeep, Jabor, cost of heat either way and 



336 ELECTRIC WELDING 

cost of time lost by making- adjustments or repairs to either 
apparatus, the electric costs per 1,000 tubes welded, is about 
one-third that of the oil-furnace method. 

The only wear on the welding machine is the surface of 
the copper dies or jaws which grip the pieces and this is so 
slight as to only require smoothing off a few times a week. 
The machine does not cost anything for heating energy except 
when the weld is being made and it is always ready for action 
as soon as the operator has placed the work in the jaws. Hence 
there is no delay in starting up the fire in the morning or 
after lunch hour nor from the fire balking at any time during 
the welding. The replacements oil welding machines in all 
the shops visited by the writer could be easily covered by $100 
during the last six years. 

In recapitulating the three methods of electric welding flues, 
it is safe to say that the flash-weld, which produces a scarfed 
joint when finished, takes the lead for simplicity of preparation, 
speed of actual welding and reliability as to percentage of 
failures in any lot of tubes. 

Next to this comes the straight scarf-weld, which requires 
machining of the ends before welding but insures a good joint 
after welding although occasionally a small leak will show 
up on the first hydrostatic test. As stated before, the per- 
centage of leaks is very low with this type of weld and 
practically negligible with the flash-weld. 

The butt-weld, which was originally employed in all the 
shops, is now only used in one shop in the whole country, prob- 
ably due to the difficulty in. making a perfect weld each time 
as compared to the ease of making a scarf weld. However, 
this one shop claims very high efficiency with a butt-weld, 
both as to tensile strength, which will average over 85 per 
cent of original tube section, and as to tightness of the joint 
under pressure. 

The principal objection offered by most shops against butt- 
welding is that should the weld prove tight under pressure, 
but still be a weak joint mechanically, it might break apart 
in service. This has happened in a few cases, allowing the 
tube to drop down in the boiler and subjecting the engine 
crew to the danger of scalding. "With a scarf-weld, which 
generally shows a tensile strength equal to that of the original 



WELDING BOILER TUBES 



337 



tube, due to the area of the weld, should the tube not be 
welded strongly as just cited and a break should occur inside 
the boiler, the scarf would prevent the tube from pulling away 
from its end and only a slow leak could result. This some- 
times actually happens with oil-furnace welded tubes. 

The Kind of Machine to Use. As there are different styles 
and sizes of welding machines being used at the present time 
on flue-welding, the writer will endeavor to specify special 
characteristics that should be sought when selecting a machine 
for this class of work, which is different from any other pipe- 
welding job. The machine should be constructed to be as 
efficient electrically as possible ; that is, the clamping jaw should 
be as close to the transformer as is practical in order not to 



Copper Jaws 





Tube 



OldTube 
End View Top View 

FIG. 280. Recessed Copper Clamping Jaws. 

have large inductive losses caused by the large gap due to 
the long secondary leads widely spaced. The fewer the joints 
between the secondary loop of the transformer and the copper 
jaws which grip the tube, the less chance will there be for 
resistance losses that cut down the heating effect gradually as 
oxides form in the joints or by dirt collecting from allowing 
them to become loose. Although the jaws should be long to 
permit thorough water cooling, it is only necessary to grip 
the pipe over a length of about 2 in. This length is bored 
out to exactly fit around the tube as shown in Fig. 280. 

The pressure device does not need to be as heavy as would 
be used on the same welding machine for joining ordinary pipe 
or solid stock, since the squeezing together of the plastic metal 



338 ELECTRIC WELDING 

is really done in the rolling machine. For fastest operation the 
clamping jaws should be operated by air cylinders so that only 
a slight movement of two valves is necessary to lock or unlock 
the tube in the jaws. 

For welding 1 up to 3-in. size tubes, a machine of 30-kw. 
rating ought to be large enough to stand constant use. Any 
form of toggle lever or screw-wheel pressure device, which 
permits the operator to stand close to the work will be suitable, 
as not over 1,000 Ib. effective pressure is required on this size 
of work to stick the ends together sufficiently hard for placing 
in the rolling machine. 

To handle up to 5f-in. superheater tubes, a machine of 
about 75-kw. rating should be employed. For its pressure 
device, an air cylinder or hydraulic apparatus may be used 
to best advantage so as to secure up to three or four tons' 
maximum effective pressure. 

For ordinary butt- or scarf-welding, a hand-operated oil 
jack may be used, although trouble has been, experienced in 
the past with this type of pressure device duo to sticking of 
the valves at critical times, often spoiling a weld. 

Plash-Welding. For flash-welding, a toggle lever or hand- 
screw wheel on small machines and an air cylinder or hydraulic, 
pressure device on large machines must be used, to effect a 
slow steady forward movement of the movable jaw in order 
to maintain the arc of the flashing, yet to have available a 
quick reverse to break the parts away should they stick too 
soon from too rapid movement of the pressure device. In small 
shops, it is advisable to install a 75-kw. machine to handle 
all sizes of tubes up to the largest superheater. If the shop 
is large enough, to keep a small machine busy all the time on 
tubes up to 3 in., it will no doubt pay to install in addition, 
a large machine just to handle the superheater tubes as well 
as any overflow lot of small tubes. While the large machine 
will handle any size, it is not so rapid in operation, on small 
tubes as the smaller one, and the bulk of flue-welding is on 
small tubes, less than 10 per cent of the total being represented 
by the larger sizes for superheaters. 



WELDING BOILER TUBES 



339 



WELDING IN THE TOPEKA SHOPS OF THE SANTA FE RAILROAD 

Supplementing the foregoing, we give the following extract 
from an article published in the American Machinist, June 
8, 1916: 

In order to give the gripping jaws of the welder good, 
clean contact the ends of the pieces are ground on the outside 
for about 6 or 7 in. back from the ends, the operator simply 




FIG. 281. Close-Up Showing Inside Mandrel. 

revolving the tube end against the grinding wheel. The ground 
pieces are sorted out into suitable lengths to form full-length 
flues when two pieces are butted together, keeping in mind 
that only two welds arc allowed to a flue. 

The butt-welding machine itself is practically as received, 
but the inside mandrel and outside rolls, together with the 
driving mechanism, were added in the shop after considerable 
experimenting. Without these the method would be a failure. 

A close-up view of the machine, from the back, is given 
in Fig. 281. This shows the mandrel A that works inside the 



340 



ELECTRIC WELDING 




FIG. 282. -Flue Parts Ready for Welding. 




PIG. 283. Flue Ends Just Beginning to Heat 



WELDING BOILER TUBES 



341 




FIG. 284. Almost Hot Enough for Welding. 




285. Rolling Out the Upset Metal. 



342 ELECTRIC WELDING 

flue as the outside is rolled between the three rolls after th 
parts have been heated and butted together. The action c 
the mandrel and rolls is to take out the upset and give a wel 
that is smooth on the outside and with very little extra mete 
inside. The gripping jaws are water-cooled, and the operatin 
air cylinders arc plainly shown. 

Fig. 282 shows two parts of a flue in place in the jaw 
and illustrates how it is slipped over the mandrel. It wi 
be observed that the mandrel does not extend far enoug 
beyond the rolls to interfere with the welding or become heate 
from the current passing between the jaws. As it is impossibl 
always to have the two parts to be welded of the same thick 
ness, the setting of the pieces in the jaws must be done wit 
judgment. If one piece is thinner than the other and the 
were both set in the jaws the same distance out, the thin on 
would burn before the thick one was hot enough to wel 
properly. To avoid this, a thick and a thin piece are place 
about as shown at A and B. In this case the thick one is a 
A and the thin one at B. As the thick one is in closer to th 
jaw, it will heat faster. The thin one, being set out farthei 
gives practically the same amount of metal for the current t 
heat. The result is an even heating and a perfect 'weld. 

Fig. 283 shows two pieces the reverse of the ones just sliowr 
As the work gradually heats, it looks as in Fig. 284. At th 
proper heat, the operator butts the work together to form th 
weld, which leaves a considerable amount of upset. He the 
shoves the. tube along over the mandrel until the weld is b( 
tween the rolls, when he throws in the clutch and brings clow 
the upper roll. The work spins between the rolls, as show 
in Fig. 285 and the result looks almost like a new 7 tube. 



CHAPTER XV 

ELECTRIC WELDING OF HIGH-SPEED STEEL AND 
STELLITE IN TOOL MANUFACTURE 

The cost of solid high-speed cutting tools is high. Ai the 
same time their remarkable cutting qualities make them a 
necessity in up-to-date shop practice. The electric process of 
butt-welding has made it possible to obtain all the advantages 
of a solid high-speed cutting tool and yet at a cost that is 
not a great deal higher than the ordinary tool-steel product. 
Stellite, which has recently become more widely known, has 
been rather limited in its use owing to the fact that it cannot 
be machined, and it has been thought by many that it could 
not be successfully joined to any other metal for holding it. 
This has limited its use to special forms of toolholders, which 
are often very clumsy in getting into difficult corners on 
special shapes. The electric process of butt-welding has made 
it possible to join Stellite bits of any common size and shape 
to a shank of ordinary steel, giving all the advantages of a 
solid cutting tool and yet employing only a small amount of 
the Stellite metal just where it is needed for cutting. 

The Thomson welding process consists of passing a large 
volume of electric current at a low pressure through the joint 
made by butting two pieces of metal together. The electrical 
resistance of the metals at the contacting surface is so great 
that they soon become heated to a welding temperature. Pres- 
sure is then applied mechanically and the current turned off, 
thereby producing a weld. The metal is in full view of the 
operator at all times instead of being hidden by the coal of 
a forge or by flame in an oil furnace. No smoked glasses or 
goggles are required any more than would be if welding by 
the forge method. Due to the way the metal is forced together 
there is no oxidation such as there would be in an open fire 
and therefore no welding compound is ordinarily required. 

343 



344 ELECTRIC WELDING 

It is this feature alone which makes it possible to weld high- 
speed steel and Stellite, the former being very difficult to weld 
by the forge method and the latter practically impossible. 
With this process of electric welding the heat is first developed 
in the interior of the metal. Consequently, it is welded there 
as perfectly as at the surface. When welding with other 
methods, however, the outer surface is heated first and very 
often the interior part does not reach welding heat, the result 
being an imperfect weld. There is no blistering or burning 
of the stock when welding electrically, whereas it certainly 
requires a very expert welder indeed to secure the proper heat 
on high-speed steel in a forge fire without burning at some 
point". The process is the most economical known, due to the 
fact that no energy in the form of heat is being wasted in 
heating more of the material than is required to make a weld 
and as soon as it has been completed the current is turned 
off so that the machine then is not using up any energy what- 
ever. The operator has complete control of the current at all 
times so that he can obtain any color desired on the metals, 
where are always visible, and waste by accidental burning of 
metal is reduced to a minimum. 

The only preparation of stock necessary for welding by this 
process is that when very rusty or greasy it should be thor- 
oughly cleaned, as the presence of either rust or heavy grease 
affords poor contact with the copper clamping jaws, retarding 
the flow of electricity and seriously reducing the heating effect. 

It is often asked if the electric current has any effect on 
the welded metal. This question arises from the fear that there 
may be some mysterious condition connected with electricity 
that will change the characteristics of the metal, particularly 
of high-speed steel or Stellite. The answer is, of course, in 
the negative, as the only effect of the electric current is to 
heat the metals being welded. 

The rapidity of work will depend largely on the operator, 
the size and shape of the pieces to be welded and the size of 
machine being used, as there is a wide range in welding time 
between heavy pieces requiring careful alignment in the clamp- 
ing jaws and light pieces which can be rapidly and easily 
handled. 

Welding High-Speed to Low-Carbon Steel. In tool welding 



ELECTRIC WELDING OF HIGH-SPEED STEEL 345 

there are various kinds of welds to be made, which require 
different designs of holding jaws and often two distinct types 
of welding machine. 

Three butt-welding machines shown in Figs. 286, 287, and 
288 are especially suitable for welding drills, reamers or other 




FIG. 286. Thomson 10-A6 Butt-Welding Machine. 

tools that can be made up of a combination of high-speed and 
low-carbon steel. The machine shown in Fig. 286, known as 
the 10-A6 machine, will weld iron or steel rods from to f in. 
in diameter, or an equivalent cross-section in squares, rectangles 
or flats. An operator can make from 50 to 200 welds per hour, 
According to the size and nature of the work being handled. 



346 



ELECTRIC WELDING; 



The clamps are of the horizontal operating type, adjustable 
for different sizes of stock as well as for horizontal alignment 
of the work. A close-up view of the left-hand clamping 
mechanism is shown in Fig. 287. The jaw blocks are water 
cooled and have a maximum movement of 1| in. by means 
of the hand-operated clamping levers. There is also a possible 
-f-in. adjustment of both front and rear jaw blocks. Stops 
are provided for backing up the work. There are four copper 
jaws to a set, two being used on each clamp. These jaws are 




PIG. 287. Closeup View of Left-Hand Clamp. 

2 1 / 2 iii. square by l r /io * n - thick. The pressure device for 
forcing the heated ends of the work together is a haiid-1 ever- 
operated toggle movement, which enables the operator to "feel" 
his work. This toggle device gives a movement of 1 in. to 
the right-hand jaw. The maximum space possible between 
the jaws is 3 J in. There is an automatic current cutoff mounted 
on the machine. The standard windings are for 220, 440 and 
550 volt, 60-cycle alternating current. The current variation 
for different sized stock is effected through a five-point switch 



ELECTRIC WELDING OF HIGH-SPEED STEEL 



347 



mounted on the machine. Standard ratings are 15 kw., or 
25. k.v.a., with 60 per cent, power factor. This size of machine 
covers a floor space 43X57 in., is 65 in. high and weighs about 
1100 pounds. 

The machine shown in Fig. 288, or the No. 6 machine, is 
for heavier work, its capacity being from J to 1 in. in diameter 
on iron or steel rods, or the equivalent in other shapes. Its 
production is from 50 to 125 welds per hour. The maximum 
jaw opening is 3 in. ; the four jaws are of hard-drawn copper, 
2JX2- in. and 1J in. thick; toggle-lever movement 1-J in.; 




FIG. 288. No. 6 Butt-Welding Machine. 

maximum space between jaws, 4 in.; current standards are 
the same as for the previous machine. There are 10 points of 
current variation for different sized stock, effected through 
double-control switches mounted on the machine. Standard 
ratings are 30 kw. or 45 kva., with 60 per cent, power factor. 
The jaws are air cooled, but the copper slides to which the 
jaws are bolted, as well as the secondary copper casting of 
the transformer, are water cooled. It occupies a floor space 
22X44 in. and the height to center line of the jaws is 37-J- in. 
The weight is 3100 Ib. Its operation is practically the same 
as the first machine described. 

Another machine of very similar characteristics is shown 



348 



ELECTRIC WELDING 



in Fi 289 This is known as the Special 5-D machine and 
is intended for the use of makers of small taps and twist drills 
up to * in in. diameter. It has very accurate adjustments on 




PIG. 289. Special 5-D Machine. 



the clamps and special jaws with steel inserts to prevent wear 
To use these, however, requires that the pieces to be welded 
must be finished to uniform size so as to accurately fit the jaws 
in order to conduct the current properly. 



PIG. 290. Stellite-Tippcd Roughing Drills 




The machines shown in Figs. 286 and 288 are not only 
<rood for welding the steels mentioned, but also for Stelhte 
work samples of which are shown in Fig. 290, since the com- 



ELECTRIC WELDING OF HIGH-SPEED STEEL 



349 



monly used bits of this metal are within their range. The 
hand-lever toggle action is quicker and is better suited to this 
work than the hydraulic-pressure device used on some of the 
larger machines. 

In welding twist drill or reamer blanks, such as shown in 
Fig. 291, not over in. in diameter, it has been found practical 




PIG. 291. Twist-Drill Blanks Just Welded. 

to use a pair of jaws on each side that will handle all work 
from the smallest up to the -in. size. These jaws are made 
as shown in Fig. 292. The two rear, or movable, jaws on each 
side of the machine are flat faced, while the front, or stationary, 
jaws, have a V-groovc cut in them just deep enough to give 
clearance for the smallest size of stock to be handled in contact 



Round Stock 
being welded 



MOVABLE 
DIE 




STATIONARY 
DIE 



Section Through Dies oindWorK 
FIG. 292. Copper Jaws for Various Sizes. 

with the face of the opposite jaw. The work is held in the 
jaws with a three-point contact, which has been found to be 
sufficient for stock of this size, although it is not to be recom- 
mended for larger work, since not enough current could be 
carried into the pieces without applying pressure sufficient to 
squeeze the work into the surface of the copper jaws. 1 his 
would soon spoil all accuracy of alignment of the V-grooves. 



350 



ELECTRIC WELDING 



In this connection it may be well to mention that a weldin 
machine is not a micrometer and the welding of finished piece 
is not recommended in commercial production, although sue 
welding is done right along for special, jobs. By "speei* 
jobs" is meant the putting on of an extension to a drill, ta 
or small reamer and the like. 

In welding high-speed to low-carbon steel the low-earbo 
steel should project approximately twice as far out from th 
jaws as the high-speed steel does in order to equalize as nine 
as possible the heating of the two pieces. 

Where a tool is to be made with a head larger than, th 
shank, as shown at A t Fig. 293, holding copper jaws shoul 



HIGH- 
SPEED 
STEEL 


\ . 

h' 


WELD 


- - - |A 
LOW-CARBON STEEL C 

1 V 


(A) 




LOW CARBON 
TELL 




(a) JAWS OF WI:LDCR> GROOVED , ^ . 

FOR ROUND STOCK (Dj 



End View 
FIG. 293. Copper Jaws for Holding Large Heads and Small Shanks. 



be made as shown at D. In work of this kind the dimensio 
B should always be about one-half of the diameter of C. Tli 
same rule holds good with this type of tool blank when placin 
it in the jaws as with steel of the same relative size; that ii 
the low-carbon steel should project about" twice as far froi 
the jaws as the high-speed steel since the high-speed steel ha 
the higher resistance and has a tendency to become phisti 
sooner. To still further reduce its tendency to heat up quickb 
the resistance should be reduced as much as possible by bavin 
the jaws as good a lit for the high-speed piece as it is possibl 
to make them. Where different sixes are to be welded it : 
advisable to have special holding jaws for each separate six 
of high-speed steel head, although the low-carbon steel piece 
may be held in V-grooved jaws made up to hold several size 



ELECTRIC WELDING OF HIGH-SPEED STEEL 



351 




352 



ELECTRIC WELDING 



This is the practice of some of the largest makers of reamers 
and large drills. 

The actual use of the machines shown for the work outlined 
is simplicity itself. The work is placed in the respective jaws 
and securely locked in place by pulling forward the two levers 
shown projecting upward on each machine. In addition to 
the grip of the jaws the work is kept from any possible slip 
by means of stops against which the outer ends of the work 
are butted. With the work solidly in place the operator pulls 




FIG. 295. Close-up of Machine with Work in Jaws. 

on the pressure lever at the right of the machine until the 
ends of the work are in firm contact, lie then turns on the 
current by means of a push button conveniently located in the 
pressure lever, and when the proper heat is reached, which 
is judged by the color, the push button is released. This shuts 
off the current and the operator then applies full pressure and 
the weld is made. 

The maximum capacity of the largest of the throe, rnac.hincs 
described is 1 in. round or its equivalent in other shapes. For 
larger work a machine similar to the one shown in Fig. 294 



ELECTRIC WELDING OF HIGH-SPEED STEEL 



353 



is used. This is known as a No. 9 butt-welding machine, and 
its capacity is from -| to 1{- in. ; the output is from 50 to 100 
welds per hour; the maximum jaw opening is 1$ in.; the four 
hard-drawn copper jaws are 3 in. high, 3|- in. wide and 1J in. 
thick; the pressure device is a 5-ton hand-operated hydraulic 
oil jack ; maximum movement with jack, 2 in. ; maximum move- 
ment with one stroke of jack, -[- in. ; maximum opening between 
jaws, 4: in.; standard windings the same as for the previous 
machines; standard ratings, 40 kw. or 55 kva., with 60 per 




FIG. 296. Steps in the Making of a Large Reamer. 

cent, power factor ; width of machine, 27 in. ; length, 60 in. 
height, 46 in.; weight, 3900 pounds. 

A closeup of this machine, with a large reamer blank in 
the jaws, is shown in Fig. 295, and progressive steps in the 
making of the reamer are shown in Pig. 296. The high-speed 
steel piece is 3 in. long by If in. diameter, and the machine- 
steel piece is 6 in. long. 

Two other machines (10-B and 40- A2 models) of this type 
suitable for heavy tool welding may be mentioned. They are 
made with a capacity of from to 1J and from 1 to 2 in. 



354 



ELECTRIC WELDING 



The first of these has a hand-operated pressure device capable 
of exerting a pressure of 12 tons and it weighs 7800 Ib. The 
second has a pressure device which receives its initial pressure 




FIG. 297. A Welded and a Finished Lathe Tool. 

from an external accumulator, which gives an effective pres- 
sure of 23 tons; it weighs 8000 Ib. and is 64X105X48 in. high. 
The Welding of Other Than Round Tools. The welding 

..-WELD 



r 

\HIGH~SPEED 
\ STEL 


LOW-CARBON STEEL 



FlG. 298. How the Parts Are Arranged for Welding. 

of tools similar to the ones shown in Fig. 297, intended for 
lathe or planing-machine tools, may be done in any of the 
foregoing machines. The cutting parts may be of either Stcllite 




End Vi e w ( a } DIE BLOCKS OF WELDER 

FIG. 299. How the Parts Are Clamped in the .laws. 

or high-speed steel. This kind of welding is usually employed 
by manufacturing concerns in their own toolrooms in order to 
use up odd bits of high-priced steel or Stellito. The pieces are 



ELECTRIC WELDING OF HIGH-SPEED STEEL 



355 



prepared about as shown in Fig. 298. Jaws for holding work 
of this kind are outlined in Fig. 299. 

Another way to make tools for lathe or planing-machine 
work is outlined in Fig. 300. This method may often be 
employed when the one just given could not. As can be seen, 




LOW CARBON STEEL 



FIG. 300. Method of Preparing for aii Insert Weld. 

in order to properly support the high-speed steel piece, the 
low-carbon steel shank is milled away to form a recess for 
the reception of the high-speed steel bit. The welding can 
be done on any of the machines shown provided the parts are 
not of too great cross-section. The method of recessing the 
copper clamping jaws is clearly shown in Fig. 301. 



Co) 

Jaws recessed 

to hold pieces 




Top View of Work Held Vertically 



















t ;f 

Pieces resting on 
bottom of recess 





Front View of Rear Jaws and Work 
PIG. 301. Jaws Used for Holding Work in Insert Welding. 

The perfect success of a welded high-speed tool depends 
not only on the correct welding but also upon the correct 
treatment after the welding itself has been accomplished. It 
is easily seen that if a piece of high-speed steel is welded to 
a piece of ordinary carboy steel and the joint allowed to cool 



356 



ELECTRIC WELDING 



fairly quickly in the air strains will be set up at the joint 
for the reason that the high-speed steel in cooling so quickly, 
both metals become hardened more or less but to a different 
degree. Hence if the weld is subjected to any great strain 
under these conditions it will break either at the joint or close 
by , due to the strain. It is therefore very evident tliat 
immediately after welding a piece of high-speed steel to carbon 
steel the work should be immediately put into some sort of 
furnace to "be annealed. The amount of time that the tools 
should be left in the furnace for thoroughly heating through 
and the amount of time required to allow the pieces to cool 
down to room temperature depend entirely upon the size and 

Sfa fionaryja ws, only 





rccessea 






1 1_ _'_ _ 


\ \ 


_ J 


1 


HIGH' 


CARBOH f 






SPEED 


STEEL " 






BIT 


SHANK 







Top View of WorK Meld Horizontally 
Piece resting on bottom of recess 





V 

1 




End View of Work 
In Right-Hand Jaws 



FIG. 302. Jaws Used for Stellite Butt Welding. 

character of tool being made. However, the annealing of any 
piece of any size requires that the work be left in the furnace 
heated to at least a dull cherry red for a few hours and allowed 
to cool very slowly in the furnace. 

If a welded tool is not properly annealed before machining 
much difficulty is often experienced from hard spots being 
encountered in the machining of the piece;s, which of course 
is more or less disastrous to the cutting edges of the tools being 
used in the machining process. 

The best method of hardening high-speed steel tools after 
the welding and machining depends also greatly upon the shape 
and size. 

Welding Stellite. Although the welding of the various 



ELECTRIC WELDING OF HIGH-SPEED STEEL 



357 



grades of Stellite is not difficult there is a certain knack in the 
welding and also in the clamping of the stock which must be 
fully acquired to produce satisfactory results. 

The welding should be done in a horizontal butt-welding 
machine with a quick-acting hand-lever pressure device. In 
butt-welding round drill stock or rectangular tool stock the 
pieces should be held as shown in Fig. 302. It will be noticed 
that the projection of the Stellite beyond the copper jaws 
is very short indeed while the projection of the carbon-steel 





o 


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hold pK, 

& 


-essecf i 
3 ces, 

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;| 


. 


HIGH--' 
SPEED 
BIT 


CARBON- 
STEEL 
SHANK 





Top View of Work held Vertically 





B/T i 




SHANK 








Pieces rest 
on boftoi 
recess 






77 Of 





Front View of Rear Jaws and Work 
PIG. 303. Jaws Used for Stellite Insert Weltlmg. 

piece is comparatively long. This is because Stellite has a 
very high resistance compared with the carbon steel. Since 
in this work the heating effect varies directly with the resist- 
ance of two metals the heating in the Stellite should be retarded 
as much as possible by surrounding it almost completely with 
the copper jaws. The correct amount of projection of the 
carbon steel will have to be determined by experiment in each 
case after observing with each setting of two pieces which has 
the tendency to heat the fastest. 

In welding in cutting bits of Stellite by the insert-weld 
method the pieces should be held as shown in Fig. 303. 



358 



ELECTRIC WELDING 



It will be seen from this cut that the copper jaws holding 
the small bit nearly surround it and at the same time back 
up the piece to take the pressure of the squeezing up of the 




FIG. 304. Vertical Type of Welding Machine. 

stock. The opposite jaws holding the carbon-steel shank do 
not have to grip very much of the metal but they serve to 
back it up to receive the force of the pressure. 

In the welding itself the current is applied intermittently, 



ELECTRIC WELDING OF HKUI-SPEEn STEEL 



359 



as the Stcllito usually has a tendency to heat wry rapidly, 
until the carbon steel is last approaching the plastic state. 
The current; is then held on steadily and the instant the Stellile 
metal "runs," the pressure lever is j>'iven a quick jerk as tile 
current is turned off. It will he round that with, a good weld 
there is scarcely any push up ol the stock and very little ol! the 




Pw. 305. 



u **Mah" InHtTt \\VM in it tin AV Mnt'lnw, 

'iudin^, if any, 



metal flows out at the joint, requiring little #r\\ 
to finish the tool. 

Unlike high-speed steel Stellite rc<iuires no further heat 
treatment or attention of any kind if it is welded correctly. 
When it in taken out of the welding machine the tool Is ready 
for use at once after grinding off the result ing burr. 



360 



ELECTRIC WELDING 



"Where large numbers of tools of the lathe and planing- 
machine types are to be made, such as shown in Fig. 300, 
the highest production can be obtained by using a vertical 




PIG. 306. Large 40- AV Vertical Machine. 

type of welding machine built on the lines of the one shown 
in Fig. 304. 

This machine (10-AV model) has a capacity of two pieces 
with contact areas between 0.40 and 0.30 sq. in. for pieces with 
a total thickness of J to 1| in. The production is 35 to 85 
tools per hour, depending on the size; the upper and lower 



ELECTRIC WELDING OF HIGH-SPEED STEEL 361 



jaws are of hard-drawn "copper l|X2i in. and 1|- in. thick; 
the jaw blocks are water cooled; the machine has a current 
variation through a five-point switch for different sizes of 
stock; standard windings are for alternating current 220 440 
and 550 volt, 60 cycles; standard ratings, 15 kw. or 25 kva. 
with power factor of 60 per cent. ; the pressure device is hand 
operated, giving a movement of 2 in. ; maximum space between 
jaws, 3J in.; floor space occupied, 21 X 53 in.; height, 75 in.; 
weight, 1200 pounds. 

A larger machine (20-AV model) of the same type in opera- 
tion is shown in Fig. 305. This machine gives a maximum area 
of contact ranging from 1J to 1 sq. in. on pieces with a total 
thickness from 1 up to 2 in. ; production is from 50 to 75 welds 
per hour; there is a throat clearance of 10 in.; the copper 
jaws are 2X3 in. and 1 in. thick; pressure is by hand-toggle 



UPPER DIE BLOCK 






A * if 


> 


~T~ P~ "^ WELL 

B 

V 


\LQWER DIE BLOCK 





FlG. 307. Jaws and Work Arranged for a "Mash" Weld. 

lever and spring cushion; current control, as in the other 
machines, is by push button in the lever operating through a 
magnetic wall switch; the jaw blocks are water cooled; 
standard ratings are 30 kw. or 50 kva. with 60 per cent, power 
factor; weight, 2200 pounds. 

Another still larger machine (40-AV model) is shown in 
Fig. 306. Except for its size it is but little different from 
the two just described, the main difference being the hydraulic- 
pressure device, which gives an effective pressure of 5 tons. 
This machine has a maximum contact area of 3 sq. in. and 
will weld pieces from 1| to 3 in. total thickness; production, 
15 to 50 welds; throat depth, 6J in.; jaws, 2X4X1^ in. thick; 
maximum movement of upper jaw block, 2 in.; movement 
with one stroke of lever, f in.; space possible between jaws, 
3 in.; standard ratings, 60 kw. or 86 kva. with 70 per cent. 



362 



ELECTRIC WELDING 




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364 ELECTRIC WELDING 

power factor; size, 34X60 in. by 79 in. high; weight, 3600 
pounds. 

For welding tools on these machines the relative thickness 
of the two parts should be about that shown in Fig. 307. Under 
ordinary conditions the dimension A should be about one-third 
of B in order to have the point of the weld nearest the jaw 
in contact with the high-speed steel, so that the heating effect 




FIG. 308. Pieces Grooved to Make Better Welds with Less Current. 

will be lessened and its fusion point retarded until the low- 
carbon steel has a chance to heat up properly. 

In order to obtain the best results tools wider than 1 in. 
and with a recess longer than 1| in. should be grooved as 
shown in Fig. 308. This reduces the section in actual contact, 
thereby requiring less current, is easier and quicker to heat 
and assures a better weld over the entire area of contact. 

In order to assist those who have tool or other butt-welding 
to do some useful data are given in Table XXVI. 

In Table XXVII is given the proper size of copper wire to 
use to connect up the various machines mentioned for tool 
welding. 



CHAPTER XVI 
ELECTRIC SEAM WELDING 

Seam or line welding is the process of joining two over- 
lapping edges of sheet metal for their entire length without 
the application of any solder or spelter along the joint. In 
the Thomson process of lap-seam welding, the heat is produced 
by passing a large volume of electric current through the 
edges to be welded by means of a copper roller on one side 
of the joint and a copper track or horn underneath. In. any 
electrical path, wherever high resistance is interposed, heating 
will result, and the higher the resistance to the current, the 
greater will be the heating effect. In the electric lap seam 
welding machines, the copper roller and horn arc good con- 
ductors and the joint between the edges of the metal to be 
welded is the point of highest resistance. On this account 
it is evident that the greatest heating effect will be at that 
point. As the roller passes over the joint, heating the stock 
to a plastic state beneath it, pressure is applied by springs 
on the roller which forces the two edges together as fast as 
they are heated. Since 20 P>. & S. gage or lighter metal heats 
very rapidly, the pressure and heating can be effected at the 
same instant of contact by the roller, and it is possible to 
weld as fast as 6 in. per second. 

The only preparation necessary for seam welding is that 
the stock must be absolutely clean, that is, free from any traces 
of rust, scale, grease, or dirt, if a tight, well-appearing joint 
is desired. If it is not necessary for the joint to be tight, 
it will not be necessary to have the stock so clean, although 
heavy scale or rust will obstruct the passage of current, so that . 
little or no heating effect can be secured under these conditions. 

In welding sheet brass of 22 to 30 B. & S. gage, to secure 
a perfect joint the metal should be carefully pickled and washed 
to remove all traces of grease and tarnish which tend to prevent 

365 



366 ELECTRIC WELDING 

the passage of current across the joint of the edges. The 
metal should be welded soon after pickling, as, no matter how 
carefully it may be washed, oxidation is always sure to start 
very shortly after the brass has been removed from the pickling 
acid. 

Steel, to be successfully seam welded, should not have a 
carbon content of over 0.15 per cent., for a higher carbon steel 
than this has a tendency to crystallize at the point of weld, 
due to the rapid cooling of the welded portion from the sur- 
rounding cold met a? After welding, the joint will be found 
to be about one-third thicker than the single thickness of the 
metal. It is possible, by applying more pressure, to reduce this 
finished thickness still more, but it wears more on the copper 
roller to do so. 

In welding brass, a soft, annealed metal should be used, 
for although hard-rolled brass can be welded, it does not force 
the two edges together very much and the finished joint under 
these conditions is almost twice the original metal thickness. 
However, with a soft, annealed brass the finished joint will 
be not over a third greater than the single metal thickness, 
and by applying sufficient pressure can be reduced down to be 
not over 10 per cent, thicker. 

The principal advantage of electric seam welding is that 
no spelter and no flux are required, the metal itself forming 
its own cohesive properties, which allows great speed in produc- 
tion. The greatest -efficiency of a seam welding machine lies 
not only in its welding qualities but in the use of a suitable 
jig to properly hold the work. The jig used should be made 
so as to enable the operator to place or remove the work in 
the shortest possible time, since the welding itself is very fast 
compared with any other known method of making a con- 
tinuous joint. 

In order that their seam welding machines may operate in 
every installation with the highest efficiency possible, the Thom- 
son Electric Welding Co., Lynn, Mass., build them standard 
only up to a certain point and then design a special holding 
jig to best fit the work to be done in each individual case. 
The amount of lap allowed in making lap seam welds is usually 
about twice the single sheet thickness of the metal. 

The operation of a lap seam welding machine is very sim- 



ELECTRIC SEAM WELDING 



367 



3, once the machine is set for any given piece of work for 
lich a special jig 1 has been built. After placing the piece in 
e jig and securely locking it there, the operator depresses 
foot-treadle which throws in a clutch and starts the copper 
Her across the work. By the proper setting of adjustable 
ntrol-stops on the control-rod at the top of the machine, 
e current is automatically turned oil as the roller contacts 




FIG. 309. Model 30(5 Lap Seam Welding Machine. 

ith the overlapping edges of the piece to be welded and is 
itomatieally turned off when the roller reaches the end of 
s stroke; another stop reverses the travel of the roller and 
ings it back to the starting position. The control-stops may 
: v adjusted to turn the current on or off at any point along 
le stroke of the roller for doing work with a seam shorter 
tan the maximum capacity of the machine. The roller stroke 
ay be also shortened so that the' complete cycle of operation 



368 



ELECTRIC WELDING 



will be accomplished in the shortest space of time on seams 
shorter than maximum seam capacity of any machine. In 
order to keep the copper roller from overheating in action, 
water is introduced through its bronze bearings on each side. 
This same water circulation, also passes through the under 
copper horn or mandrel and then through the cast-copper 
secondary of the transformer, so that the machine can be 
operated continually, 24 hours per day if desired, without 
overheating. 

Lap Seam Welding Machines. The lap seam welding 




FIG. 310. Details of Welding Boiler Head. 

machine, known as Model 306, shown in Fig. 309 will weld 
a seam 6 in. long in soft iron or steel stock up to 20 gage 
in thickness, or brass and zinc up to 24 gage thick. This 
machine will make from 60 to 600 welds per hour, depending 
on the nature of the work and the quickness with which the 
pieces can be placed in and removed from the jig. The copper 
horn is water-cooled and has an inserted copper track on 
which the work rests. The upper contact consists of a copper 
roller .6^ in. in diameter, mounted on a knockout shaft sup- 



ELECTRIC SEAM WELDING 



369 



ported in water-cooled bearings. Pressure is exerted on the 
copper roller by means of a series of springs on each side 
which are adjustable to give the proper tension for various 
thicknesses of stock. Current control is automatic through 
a magnetic wall switch carrying the main current. The latter 
is controlled from a mechanical switch which is thrown in or 
out by the action of the roller-carrying mechanism as it starts 




FIG. Sll.Tliomson No. 318 Lap Seam Welding Machine. 

and completes the stroke for which it is sot. Standard wind- 
ings are for 220-, 440-, and 550-volt, 60-cyclc, alternating cur- 
rent. Current variation for different thicknesses and kinds 
of stock, is effected through a regulator which gives 50 points 
of voltage regulation. A variable-snood -J-hp. motor gives a 
wide variation in the speed with which the roller may be fed 
over the work. The standard ratings for the machine are 
15 kw. or 25 kva., with 60 per cent, power factor. This 



370 



ELECTRIC WELDING 



machine covers 32X96 in. floor space, is 68 in. high and weighs 
2750 Ib. 

A close-up view of the type of roller-carrying head used 
on all the lap seam welding machines, is shown in Pig. 310. 
In this view the roller is shown operating between the clamping 
bars of a special holding jig on the horn. As the roller itself 
occasionally requires smoothing off around its contacting sur- 
face, its bearing has been designed to knock out quickly so 




FIG. 312. Large Size, No. 324, Lap Seam "Welding Machine. 

that removal and replacement of the roller is very simple and 
easy to accomplish. The cleaner the stock being welded is 
kept, the longer a roller will operate without requiring smooth- 
ing off, as dirt and scale on 8 the stock cause a slight sparking 
as the roller passes along, which tends to pit up its contact 
surface. 

The machine shown in Fig. 311, known as Model 318, is 
a larger and heavier machine than, the one previously described 



ELECTRIC SEAM WINDING 



371 

and will weld a lap scam. 18 in- * *" '" *"*' *"" ! . 

A i . T A j.-, r almilnr luit smaller machine 

metal quoted. Another very su" 1 

(Model 312) is also made for weldintf scums up to - in. 

In Pig. 312 is seen a considerably larvr maHan, Model 
324, capable of welding a lap seam up 1u L4- n. in Icn^lu 

mi i x- on a. i on -iv^lils tx'i' hour. I he inacliiiH 1 

The production is from 30 to l^U AVC ' 

covers a floor space of 36X90 irl -> iH 72 1U ' K ' " lul wol hs 
3500 Ib. All other specifications arc the sain- as K iv-u lor 

Fig. 309. 

Examples of Holding Jigs. Tlie innclunes shown may be 
fitted with numerous forms of holding jis fti.m ll.e simple 





wiiiiiniii j ^miwmmmmm^^mii^^^^p^^^^^^^^^ljjjjjl 



FiG. 313. Oil Stove Burner TuboH Ht*i f ur uul Aftr Wolihn^. 

bar clamps shown on the horns in "Ri^rs. 31 1 and .'U2, to various 
more complicated forms, some of \vlneh may IN* mounted on 
the knee below the horn or bolt eel direct tt the fact' of the 
machine column. 

The small oil stove burner tubes shown in Fig, U.'I l<n<l 
themselves nicely to the seam, welding iro*rss. rylimlriral 
pieces such, as the shell tubes for automobile iintfllrrs shown 
in Fig. 314, need a rather claborute holding ji^c. A inachiiu 1 
fitted up for tliis work is sliown in Pi^, .HT). To inM<rt -a 
muffler shell into this jig the hingred ciul is s\vuiifr outward 
and downward; the two halves of tlu* holder are spread apart 
by pressing down on the left-handle treadle; the .shell is thru 



372 



ELECTRIC WELDING 



thrust Into the holder; the treadle is released, which allows 
the holder sides to be pressed in by the springs and hug the 
muffler shell around the horn of the machine, with the edges 
overlapping enough for the weld; the end gate is then closed 
and the welding roller started over the seam. The principal 
function of the gate is to hold the muffler shell square in the 
jig and prevent it being pushed out by the welding roller. 




FIG. 314. Seam Welded Automobile Muffler Tubes. 

A jig for holding large cans is shown in Pig. 316. The 
side clamps of this jig are operated by means of the lever 
shown at the left. An end gate, shown open, is used in the 
same way as in the muffler shell jig. Work of this kind is 
of course much slower than with a smaller jig, yet it is faster 
than by any other process of closing the seams 



ELECTRIC SEAM WELDING 



373 



Bucket bodies arc held as shown in Fig. 317. The holding 
jig is made to slide in a channel bolted to the machine knee. 
The jig is slid back clear of the horn and, with the gate in 
the flaring end open, the bucket blank is inserted. The gate 




Mufllcr TuboH. 



is then closed by means of the handles the jig and work IB 
pushed over the horn to a Htop, and the weld is made as usual. 
Another application of seam welding, is to use it For welding 
the ends of strip stock together, end to end, so as to facilitate 
continuous passage of the strip through the dies of a punch 
press. A machine fitted up for this work is shown in Fig. 318. 



374 



ELECTRIC WELDING 



The ends of the two strips to be welded are inserted in the 
jig from opposite sides and the edges brought together. The 
pieces are then clamped by means of the two levers shown in 
front of the jig, which operate eccentrics over the clamping 




FIG. 316. Holding Jig for Largo Sheet Metal Cans. 

plates. The welding roller is then run over the ends as in 
other work of this kind. 

Mange seam welding differs from lap seam welding in 
that instead of the metal being lapped a slight fin or flange 
is formed along the edges of the metal parts, the flanges being 
welded together and practically eliminated in the process. This 



ELECTRIC SEAM WELDING 



375 



class of welding is especially adapted to the manufacture of 
light gago eoffee and teapots spouts or similar work. 

A machine built especially for ilauge seam welding, known 




Fit). 317. 



as Model 2(5, is shown in Fi* m The work Iwinff done in 
the welding of tin* two halven of tenp<t spouts. In the operation 
the two halves of tin- spun! are damped xeeureiy in n speeiat 
copper jig, Fig. :*20, which has been carefully hauul-^tit to 



376 



ELECTRIC WELDING 



fit the halves of the spout perfectly on the entire contacting 
area. The jig is pushed around on the flat copper table, which 
constitutes the top of the welding machine, so that the seam 
of the edge to be welded is allowed to ride along the small 




TIG. 318. Jig for Welding Ends of Metal Strips Together. 

power-driven copper roller which is mounted on a vertical 
shaft, as illustrated in Pig. 321. The halves which are welded 
by this process must be blanked out by special steel dies to 
give the correct amount of fin or flange on each edge. This 



ELECTRIC SEAM WELDING 



377 



fin is heated to the plastic sta^e by contact with the roller 
and the slight pressure applied not only forces the metal of 
the two fins to cohere but also forces the projection into a 
level with the outer surface of the spout, thus giving a finished 
job direct from the welder which is smooth enough without 




FIG. 319. Machine for Flange Scum Welding. 

any grinding to be ready for the enamelling or agate-coating 
process. 

The secret of success of this work lies wholly in the proper 
preparation of not only the copper holding-dies, but also the 
steel flanging and forming dies. A finished spout, just as it 



378 



ELECTRIC WELDING 



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380 



ELECTRIC WELDING 




PIG. 320. Jig fov Holding Teapot Spouts for Welding. 




FIG. 321. Diagram of Flange Seam Welding Operation. 




FIG. 322. A Finish Welded Teapot Spout. 



ELECTRIC SEAM WELDING 381 

comes from the welding machine, is shown in Fig. 322. The 
welded seam is barely visible. 

In order to assist those who have welding jobs to do, to 
calculate the current cost on various jobs, Table XXVIII is 
given. This table shows the approximate current consumption, 
and multiplying the rate given by the local rate charged, the 
cost of 1000 welds can be easily ascertained. 

Table XXIX is very convenient for ascertaining the size 
of copper wire needed to connect the different machines men- 
tioned to the main source of current supply. 



CHAPTER XVII 

MAKING PROPER RATES FOR ELECTRIC WELDING 
AND THE STRENGTH OP WELDS 

The uncertainty which seems to exist regarding electric 
welding rates among central-station interests, says S. I. 
Oesterreicher in Electrical World, is no doubt due to the indif- 
ference of the welding industry, which during a long period 
in the past did not assist those affected by the rates as much 
as its unquestionable duty would have suggested. 

While welding installations of only comparatively small 
sizes had to be considered say from 25 to 100 kva. no great 
harm was done by such tactics to either interest. However, 
with the installation of large equipments and the operation 
of large unit welding machines, central stations suddenly 
experienced disturbances upon their lines and in their stations, 
which were anticipated but partly and were blamed entirely 
upon the welding equipment. Thus, to protect themselves, 
central-station interests launched into a partially retroactive 
policy, greatly to the detriment of the welding industry as 
a whole. 

Since welding installations of several thousand kva. capacity 
are not unusual, it is proper that all points of doubt should 
be considered as broadly and fairly as possible, and a far- 
reaching co-operative policy inaugurated. The revenue from 
such large installations may easily reach several thousand 
dollars a month. It is therefore obvious that, from a purely 
commercial standpoint, a welding load is a very desirable 
constant source of income to the central station. 

Looking at the reverse side, it should be recalled that cen- 
tral-station engineers, on account of past sad experiences, had 
jumped to the following conclusions : 

1. That a welding installation is a very unreliable metering 
proposition. 

382 



MAKING PROPER RATES FOR ELECTRIC WELDING 383 

2. That it has a poor load factor. 

3. It has a constantly fluctuating load varying between 
extreme limits, and 

4. It has a bad power factor, 

The first important point is, no doubt, the metering. The 
time-honored opinion on one side that, due to the short period 
involved, an integrating wattmeter does not respond quickly 
enough, is contradicted by the claim on the other side that 
the deceleration of the meter disk compensates for the lagging 
acceleration. As far as the writer is aware, not the slightest 
positive proof has been offered to support either contention. 
Considering for instance a 200-volt, 300-amp., single-phase, 
two-wire wattmeter, whose disk at full load makes 25 r.p.m., 
and assuming the total energy consumption to be integrated 
within 0.2 second, it will be found that to register correctly 
the meter disk has to travel about 0.08 of a revolution. It is 
scarcely possible that by merely looking upon a meter disk 
any one could guess within 100 per cent the actual travel 
during such a short time interval. A stop watch will scarcely 
be of any assistance ; neither will a cycle recorder with an 
ammeter and voltmeter cheek be of any value, since no instru- 
ment is of such absolute dead beat as to come to rest from 
no load to full load within 0.2 second. Such methods therefore 
are of no value in ascertaining the behavior of a wattmeter 
under sudden intermittent heavy loads. 

The next step of the metering proposition was to take the 
rated energy consumption of the welding machine as given by 
the manufacturer, assume a certain load factor, calculate from 
these data the energy consumption, correct for the power factor 
and check the answer periodically on the meter dial. The 
result obtained on the meter was usually a constantly varying, 
lower energy consumption than calculated, and no doubt this 
was the cause of the great distrust of the meter. This method 
is worse than no check at all, and it is so for the following 
reasons : 

1. The energy consumption at a welder depends iipon the 
welding area of the metal, but is not a proportionate variable. 
That is, all other factors being the same, two square inches 
of a certain weld do not consume twice as much energy as 
one square inch does. Pig. 323 shows this fact plainly. It 



384 



ELECTRIC WELDING 



is also of common kno\vledge that on a spot welder the area 
of the weld varies from weld to weld just as much as the 
electrode contact area does. Assuming an electrode at the start 
as Vic in. diameter at the tip, after about 200 welds it might 
be anything from J in. to 5 / 16 i n - diameter, thus gradually 
increasing its contact area anywhere from 75 per cent to 175 
per cent. 

2. On butt welders the energy consumption does not depend 



2000 



1600 

| 

PJ400 



jJOOO 
o 

' 

| aoo 

JD 

600 

>v 

r 

400 
200 



2680 



2412 



2144 



876 3 



008 * 



340 1 

JX 

072 | 
804 



536 



26.8 



~Q ozo.4 a6 0.8 uo \z 1.4 .\& 1.8^0 n 2.4 2.6.2.8 

Welding Area of Iron in sci,. in. 

FiG. 323, Energy Consumption of Eesistance Welding for Commercial 
Grades of Sheet Iron. 

upon the size of the weld alone, but also upon the clamping 
distances. Fig. 324 gives some information about the influence 
of variable clamping distances upon the energy consumption 
of welding machines. On a butt welder, the clamping distances 
increase with the gradual wear of the electrode ; thus the above 
spot welder conditions are duplicated on butt welders also. 
3. If no compensation is made to vary the impressed emf. 



MAKING PROPER RATES FOR ELECTRIC WELDING 385 

of the welder and this is never done then the time must 
vary from weld to weld according to the condition of the 
electrode. If the time is changing constantly, the assumed 
load factor changes correspondingly ; thus there are three con- 
stantly changing factors in the estimated energy consumptions, 
beyond any reasonable approximation of the actual facts. 

A more reliable method would be a periodic oscillograph 
test, but this method is rather complicated and expensive and 
could be done only by large central stations which have both 
the equipment and the trained personnel for such work. 

Such tests, once they are made for certain types of welders 




05 



ao 



~TO \~S 2.0 2.5 3.0 3.5 4.0 
C! cum ping Distance in Inches 

,FiG. 324. Effect of Clamping Distance Between Electrodes Upon Time 
and Energy Demand. Area, 0.25 Sq. In. 

and work, will give excellent data from which to check the 
actual behavior of the standard type of wattmeter. If such 
comparisons are made, it will be found that the integrated 
energy consumption of the wattmeter will be larger than the 
oscillograph test indicates. It is not intended to claim that 
the wattmeter registers "fast. " Laboratory tests are usually 
made by skilled men, who before the test carefully ascertained 
all important factors entering into the test, as area of weld, 
condition of electrodes, welder, emf., cleanliness of material, 
etc., whereas under normal operating conditions almost no 
attention is paid by the operator to these considerations. In 
fact, if the operator works on a piecework or bonus basis, he 
will conceal as much as possible all discrepancies which have 



386 ELECTRIC WELDING 

a tendency even temporarily to curtail his earnings. The result 
of his policy has a very important effect upon the wattmeter. 

Summing up the metering proposition and speaking from 
experience on large welding installations with capacities over 
250,000 sq. in. of welding per month, where ten to fifteen butt 
welding machines are constantly thrown on or off the supply 
circuit, it is safe to claim that in such installations the standard 
alternating-current integrating wattmeter is on the job. 

'The Load Factor. The present-day tendency in resistance 
welding practice is to perform the weld as quickly as possible 
without injury to the metal, but fast enough to prevent im- 
perfection at the weld. Having in mind large welders with 
5 to 15 sq. in. weld capacities, this tendency will give a unit 
load factor not much over 10 per cent per welder. From the 
central-station viewpoint, this factor is certainly very low and 
undesirable. 

However, two important circumstances alter the condition 
considerably. The first point is that in large installations one 
large welder will not suffice to do all the required work, there- 
fore several will have to be installed. Owing to the big energy 
demands these large welders never operate simultaneously. 
While one welds the next is cleaned, the third is prepared, the 
fourth is waiting for the signal to weld, etc. ; thus the load 
factor of the installation as a whole is considerably over 10 
per cent and nearer to 20 per cent. Another natural circum- 
stance of large installations is the fact that not all work requires 
large welders. There are usually ten to fifteen smaller welders 
installed, of which 30 per cent might work intermittently with 
the larger welders. Thus it will be seen that the load factor 
is bad only in small installations connected to small central 
stations, while large installations, which necessarily must 
receive their supply of energy from comparatively larger cen- 
tral plants, have rather a good aggregate load factor, reaching 
well up to 25 to 30 per cent. 

Another point for consideration is the fact that, owing to 
its temperature, large work cannot be handled immediately 
after welding. The work must cool off before additional opera- 
tions can be performed upon. it. The cooling takes some time. 
In several instances it was found desirable to shift the working 
hours of the welding crew several hours ahead or behind the 



MAKING PROPER RATIOS FOR ELECTRIC WELDING 387 

working hours of the rest of a .factory, .for the sole reason that 
there 1 ! should he on hand sufficient cool welded work for the 
successive, manufacturing steps. I f this time-shifting is selected 
to coincide with the low-point period of the load .factor of a 
central station, then there results an actual all-around improve- 
ment. For this the welding installation should he entitled to 
a certain proportionate consideration. 

Maximum Demand. -Owing to the instantaneous severity 
of a, welding load, demand upon a supply station seems to he 
of considorahle importance. However, the shifting of a, load 
factor toward an off-load period, as described, will certainly 
take the severest effects off the system. Under such conditions 
regulation of the supply system suffers only in small plants, 
and only in places where lighting and power loads are fed 
from the same mains 

But large welding installations are usually direct-connected 
through transformer hanks to the station buses, where the 
fluctuating character of the welding load will be almost negli- 
gible and certainly will not affect the regulation of a system 
in a degree commensurate with the si/.e of the connected weld- 
ing installation. Of course in all these discussions it is assumed 
that the station apparatus, transformers and supply feeders 
art 1 properly selected, with equipment properly calculated to 
fit the particular welding load. In the past this has not always 
been the case, and this is one of the causes of so many different 
maximum demand charges. 

The ratio which the maximum demand should bear to the 
connected load will always remain a local issue between 
produce*! 1 and consumer. The ratio should, however, be made 
to depend on the average kilovolt-ampere energy demand of 
all the welders (and not on their rated capacities as given 
by the manufacturer) and of the rated capacity of the primary 
supply installation. If the welding customer bears a part of 
the installation charges caused by larger transformers and 
larger supply mains, be should benefit by the resultant mutual 
advantages. However, no demand charge should be based 
upon a mixed welding and motor loud supplied from a common 
primary installation. The importance of this claim will he 
more evident if it is stated that by separating a certain mixed 
welding and motor circuit, and by installing an additional 



388 ELECTRIC WELDING 

100-kw. equipment, the maximum-demand charge in a single 
supply circuit in one month was reduced over $200. 

To be sure that no more disturbing overloads are thrown 
upon the line than have been contracted for, overload relays, 
time clocks and maximum-demand indicators will be found 
sufficiently reliable for all honest purposes on both sides of 
the controversy. 

Proper grouping of the single-phase welding loads upon 
a three-phase supply system, will give perfect satisfaction in 
almost all installations but those of small size. 

Power Factor. So much has been said and so much worry 
caused about the poor power factor of a welding installation 
that it is now universally accepted that tt&Jg<^^ 
bad^and nothing further is done about it. The outstanding 
feature about this condition is that the central stations, in a 
most unfortunate moment, decided to "penalize " the power 
factor. It is not the charge for the condition, but the adoption 
of the word for the charge, which makes the customer balk 
and is the cause of no end of distrust toward the welding 
machine. The word "penalty" conveys to the lay mind the 
impression that a poor power factor exists only with welding 
installations, and naturally the conclusions are not flattering 
for the welding equipment. 

No attempt is made here to describe the well-known methods 
of improving the power factor of a welding installation with 
synchronous apparatus. The adoption of such methods is more 
of a commercial than an engineering problem. Upon investiga- 
tion it will be found that, with few exceptions, it is cheaper 
to pay for the poor power factor than to invest in additional 
apparatus. However, the average power plant usually has, 
besides a welding installation, a number of other consumers, 
the effects of whose poor power factor are felt in considerable 
measure at the generators. If all such sources are investigated 
and segregated upon one common bus, together with a welding 
load, it might be found that either a synchronous or static 
apparatus would more than pay for itself, if installed at the 
proper place. 

If this fact is explained to a welding customer, there can 
be no doubt that he will be only too eager to bear a certain 
proportion of the investment for a special apparatus and thus 



MAKING PROPER RATES FOR ELECTRIC WELDING 389 

secure 01* himself a better rate for the consumed energy. With 
proper co-operation between the central station and the welding 
customer on all these points of mutual interest, much misunder- 
standing and distrust could be eliminated, benefiting all parties 
concerned in the welding industry. 




FILLET AND SPOT WELDED 




FILLET WELDED 




RIVETED AND FILLET WELDED 




SPOT WELDED 




RIVETED JOINT 
FIG. 325. Welded and Eiveted Joints. 



Strength of Resistance Welds. In some of its applica- 
tions, spot welding affords a method of preliminary joining 
ship hull plates, after which the required additional strength 
is obtained by arc welding. The Welding Research Sub-Com- 
mittee made some progress in comparing, combined spot and 



390 



ELECTRIC WELDING 



arc welds, and combined rivet and arc welds with riveted, 
spot-welded and arc-welded joints. It is not a question in 
such an investigation, of spot versus arc welding, but of spot 
and arc welding. 

According to Hobart, test specimens arc made up of the 
following combinations : 

(a) Spot and fillet welds (two samples made) 



5 6 78 9 




FIG. 326. Spot- Welding Tests on Hoop Iron. 

(b) Fillet welds, made by welding fillets about two inches 

in length at the ends of overlapping plates (two' 
samples made) 

(c) Kivet and fillet welds (one sample made) 

(d) Spot welds, made by welding two spots approximately 

one inch in diameter, on the plates (two samples 
made) 

(e) Eiveted joint, made by riveting a ~X4X12 in. plate 

with two plates |X4X16 in., using two f in. rivets 
and a four inch plate lap (one sample made) 



MAKING PROPKH KATir. FOR KLKCTUlt 1 \VKLDIN(i Mi 

The way these plates were Fastened is illustrated in Fig. 
325. Tlic results of the tests were as .follows: 

(a) Spot and fillet weld ultimate load 50,:>50 Ib. 

(h) Wild, wolds ultimate loud ;J7,<)00 Hi. 

(<0 Rivet and fillet welds ultimate load :ir>,<)()() tb. 

(d) Spot welds ultimate, load .-S,()00 Ib. 

(o) KivoUul joint ultimate load 1. '5,000 Ib. 

Spot-Welding Tests on Hoop Iron, The Thomson Co. made 
up ten samples of spot-welded, riveted, butt-welded and plain 
pieces of hoop iron, and had them tested in the Lnnkenheimer 
laboratory. The pieces after testing are shown in Ki^-. Ite(>. 

The results were as follows: 

No. 1. Spot-welded in one place- broke at weld at. l,fUfi pounds. 

No. I!. Spot -welded in two places, also (wo rivets broke at rivets at 

l,r>f>fi pounds. 
No. .'I. Spot -welded in three places broke outside weld at li,7lf pounds, 

(Notice elongation of metal, ) 
No. *1. Spot -welded in three places, also three rivets broke at rivets at 

" ,()")"> pounds. 

No. f>. Solid lap weld broke nntsiilc weld at 7",!o pounds. 
No. <"> Butt welded t broke ;it weld at lV> "*> pounds. 
No. 7, Spot -welded in one place, and riveted once broke at rivet at iHio 

pounds, 

No. S. Solil lap weld broke at \vell at l!1l!,*" pounds. 
No. 1*. Spot -welded in two places broke at weld at l],7fi pounds. 
No. H). Plain piece of ho<p iron, not welded- pulled apart at U,<iw pounds. 

Taking the average* of the breaking points of ihr jhrce 
pieces, U, 5 and 10, thai broke in the pieces themselves, \v< ( 
^et approximately 2700 Ib, as the strength of the hoop iron. 
This furnishes a basis for percentage calculations if such are 
desired. By f^roupinK six of the tests, we f*et the following 
results for comparative purposes: 

Tc8t Nt. 1. One Hput'Wcld: broke at UttJfi pouttda 
Test No. 7. One Rivet: broke at Witt pounds. 

The weld Mtnoil over *JO per cent more than the rtvefn 
Test No. i>. Two Spot \Vehls: broke at iM!7"> poundM, 
f fcKt No. L*. Two Ktvefs: broke at I ,.">;"," pounds. 

Tin* weld Htood over lio per cent more than the fixelM. 
Tent No, .*{. Three Sjt- \\VMn: broke outKitle weld at ,7l." pottndrt, 
Tc>Mt No. {, Three Uivvt^: fcr* apart nt -,orr ptninds, 



392 



ELECTRIC WEjuDING 



Strength of Spot-Welded Holes. It sometimes happens that 
a hole will by mistake be punched in a plate where it is not 
needed. The spot welder can be used to plug such holes and 
make the plate as strong as, or stronger than, it was originally. 
It is first necessary to make a plug of the same material as 
the plate which will fit in the hole and which is slightly longer 
than the plate is thick. The length required will depend on 
the snugness of the fit of the plug in the hole ; there should 
be enough metal in the plug to a little more than completely 
fill the hole. The plate is placed in the welder with the hole 
which is to be filled centered between the electrodes, the plug 
is placed in the hole, the electrodes brought together upon it, 




JTiG. 327. Sample Plates with Holes Plugged by Spot-Welding. At the 
Eight Is Shown a Plate with Plug in Place Previous to Welding. 

and upon the application of pressure and current the plug 
will soften, fill the hole, and weld to the plate. 

Fig. 327 shows, at the extreme right, a piece of |-in. plate 
with a punched hole which is to be plugged, and the plug in 
place previous to welding. The three pieces at the left of 
the photograph have the plugs welded in place. A fact which 
the illustration does not bring out very clearly is that the 
surface, after the plug is fused in, is practically as smooth as 
the remainder of the plate, the maximum difference in thick- 
ness between the plugged portion and the remainder of the 
plate being not more than 1 / 32 in. on a -J-in. plate. 

That there is a real and complete weld between the plug 
and .the plate is shown by Fig. 328. The four samples illus- 



MAKING PROPER RATES FOR ELECTRIC WELDING Wtt 

trated were placed iu a testing' machine and broken by longi- 
tudinal pull, with the interesting result that not one of the 
three plugged plates broke through the weld. The sample at 
the right was broken to give an indication of the strength 
of the samples after punching and before welding. Two sam- 





Fio. ,'ll!S.- -PlatcM Shown in Fig. .'JU7 After Pulling in th< TeHting 
Note. That All Welded Plates Brnke Outside the Weld. 

TAIIJLH XXX. 



No. of 
Sample 


Description 
of Sample 


lion 

In. 


\ 

Tensile 

*" T Lb g 


Locution 
of 


1 


Punched i f fin, dia- 


2 by 


59,320 


Outsuie 




meter hole and 


J ; 4 




weld 




plugged by welding 








2 


Punched A-in, dia- 


2 by 


59,320 


Outside 




meter hole and 






wdd 


3 


plugged by welding 
Punched A-in, dia- 


2 by 


59,350 


Outside 




meter hole and 


J/2 




weld 




plugged by^weldiog 








4 


Punched A-*n. dia- 


2 by 


3 1 , 51)0 


Through 




meter hole but not 


7$L 




hole' 


5 


plugged 
Original bar, not 


2 by 


50,230 


Through 




punched 


l'2 




center 





Original bar, not 


2 by 


51) , 000 


Through 




punched 


M 




center 



394 ELECTRIC WELDING 

pies (not shown) from the same bar but without the punched 
holes were pulled to find the original strength of the material. 
The results are given in Table XXX. 

It is interesting to note that the average of the breaking 
point of the three samples punched and plugged was 59,330 
lb., whereas the average for the two samples not punched was 
59,115 lb., or 115 lb. less. This proves that there was no weak- 
ening of 'the surrounding plate, due to the weld. That the 
ductility of the welded section was somewhat decreased is 
shown by the photographs of the samples after pulling. 

The actual welding time required for plugging a hole in 
a plate is from five to ten seconds. Of course, it is necessary 
to have a plug of the proper size, but a variety of plugs, of 
all the standard rivet hole diameters and of lengths suitable 
for the various thicknesses of plates, could be made up and 




FIG. 329. Straight Rods Spot-welded to Angle Iron and then Bent by 
Hammer Blows, the Angle Being Supported only by the Unwelcled Flange. 

kept in stock in the yard. The method described should prove 
a valuable means of salvaging material which otherwise might 
have to be scrapped. 

Strength of Rods Mash- Welded to Angle Iron. While no 
figures are available, the illustration Fig. 329 will give an 
idea of the strength of welds where rods are mash-welded to 
angle iron or plate. Three straight iron rods were welded 
to an angle iron and then hammered over with a sledge, as 
shown. This is a very severe test of a weld. 

Strength of Electric Resistance Butt-Welds. According to 
Kent, tests of electric resistance butt-welded iron bars resulted 
as follows: 

32 tests, solid iron bars, average 52,444 lb. 

17 tests, electric butt-welds, average 46,8136 lb. 



.MAKING PROPER RATES FOR ELECTRIC WELDING 395 

This is an efficiency of 89.1%. 

Presumably the welds were turned to the size of the bars, 
Ithough Kent docs not say so. 

In a number of tests on draw-bench mandrels the following 
esults were obtaiiied. The mandrels consisted of one piece 
f g in. dia., 30-40 point carbon steel, welded on to another 
iecc of g dia., 110 point carbon Carnegie electric tool steel 
[o. 4. The low carbon ends were drilled and threaded to 
Qceive the stud of the bench rod, and the high carbon ends 
'ere upset, machined, and used as working heads. Six sam- 
les of each kind of steel were prepared and sent to the Thom- 
Dn Electric Welding Co. of Lynn, Mass., to be welded. 

After welding the mandrels were subjected to the follow- 
ig heat treatments and operations : 

1. Head-end annealed after upsetting. 

2. Head-end machined, and hardened by quenching in 

water. 

3. Mandrels worked on draw benches until worn out or 

broken. 

4. Entire length of mandrels heated to 1450 F. and cooled 

in air. 

5. Mandrels subjected to tensile test to destruction. 
Mandrel No. J?. Pulled 5125 ft, of 1X-H2 in. to -JX.107 in., 

7 point carbon. Rather heavy pull. Broke stud once, and used 
gain after replacing same. Pulled to destruction in standard 
\sting machine, and failed 2-J- in. below weld on low carbon end, 
t a stress of 59,000 Ib. per sq. in. AVeld stronger than low 
arhon round. 

Mandrel No. 2. Pulled 3360 ft, of 1 3 / 10 X.46 in. to Y 4 X.38 
i., 17 point carbon. Not badly worn at end of load. Pulled 
) destruction in testing machine, and failed 1 in. below weld 
n low carbon end, at a stress of 58,800 Ib. per sq. in. "Weld 
,ronger than round of 30-40 point carbon of same cross-section. 

Mandrel No. 5. Pulled 2400 ft. of 1X-H2 in. to 5X-107 
i., 17 point carbon. Broke at stud and replaced by another 
landrel. Pulled to destruction in testing machine, and failed 
n weld at stress of 58,000 Ib. per sq. in. "Weld 98% efficient, 
2f erred to mandrel No. 1. 

Mandrel No. 4. Pulled 2250 feet of 1 3 / 4 X.200 in. to 
'/KjX-200 in., 17 point carbon. In good shape at end of load. 



396 ELECTRIC WELDING 

Pulled to destruction in testing machine and failed on weld, 
at a stress of 56,900 Ib. per sq. in. Weld 96% efficient, referred 
to mandrel No. 1. 

Mandrel No. o. Pulled 402 ft. of 1X-H2 in. to JX-108 in., 
17 point carbon. Broke off at stud of rod, tube being unduly 
oversize. Pulled to destruction in testing machine, and failed 
on weld at a stress of 53,700 Ib. per sq. in. Weld 91^ efficient, 
referred to mandrel No. 1. 

Mandrel No. 6. Mandrel broken at thread on first tube. 
Tube over-size. Mandrel lost. 

Conclusion. Out of five mandrels subjected to a tensile 
test to destruction after being worked on the benches, two 
show that the weld is stronger than the 30-40 point carbon 
round solid rod, and the other four showed efficiency of 91% 
to 98%, referred to 59,000 Ib. per sq. in. The maximum 
required efficiency is not over 70%. Therefore the mandrels 
passed all requirements for strength and service. 

Strength of High Carbon Steel Welds. In order to throw 
some light upon the chemical and physical changes induced by 
the welding process, pieces of 0.97 per cent carbon drill steel, 
of | in. diameter, were studied after butt welding, writes E. E. 
Thum in Chemical and Metallurgical Engineering, Sept. 15, 
1918. Test pieces of the original stock and of both annealed 
and unannealed welds were made by mounting in a lathe, re- 
moving the excess metal of the fin, and then turning or grinding 
a short length of the bar accurately to a diameter of ^ in., 
with the weld in the center of the turned portion. In the 
unannealed welds, the turned portion was but in. in length 
in order that the failure would be forced to occur within the 
portion of the bar altered in constitution by the welding heat. 
Tension tests of the unannealed welds showed, in all cases, a 
failure with little or no necking occurring at the end of the 
turned portion that is to say, farthest from the weld and in 
the softest portion of the test piece. The strength this de- 
veloped was much higher than even the strength of the original 
steel, and it is clearly evident that all parts of this weld have 
a higher ultimate strength than the original bar. The average 
results of the tension tests follow: 



MAKING PROPER RATES FOR ELECTRIC WELDING 397 

Ultimate Contraction Elongation 

Strength Lb. in Area, in 4 In. 

per 8q. In. Per Cent I'er mil 

Original tool steel 114,100 - 12 1() 

Unannealed weld 158,700 2 :{ 

Weld annealed at 750 C. (1382 F.).. 100*800 24 1(5 

In the annealed bars failure always occurred at the wold, 
accompanied by considerable necking, strictly limited to tho 
close proximity of the point of failure. 

The results of a series of tests on butt- and spot-welds made 
by G. A. Hughes, electrical engineer of the Truseon Steel Com- 
pany, Youngstown, Ohio, were reported as follows: 

TESTS MADE ON BARS OF SOFT STEEL, 1 IN. SQ., BUTT-WKUJKU AND 

MACHINED TO THE SIZE OF THE BAK. 

Test No. Volts Amps. Kw. l'mv<>r PaHor 

1 220 220 40. iM 

2 220 220 40. 1M 

3 220 210 :J9. S'l 

4 218 210 39.5 ' NO 

5 220 210 :U). ! 

All tension tests were pulled at a speed oi f \t> in. per min. 
Nos. 1, 2 and 3 were pulled, while Nos. 4 and 5, were shoaml. 
On the different tests, No. 1 failed in the weld at 48,800 11>. ; 
No. 2 failed in the weld at 52,300 lb.; No. 3 failed hack of the 
weld at 50,100 lb. ; No. 4 failed at 51,500 11). and No. 5 at 
50,300 lb. 

These tests indicate that the ultimate shearing strength of 
such a weld closely approaches the ultimate tensile strength. 

Pieces of soft steel, Vic in. thick and 5 in. wide, with an 
ultimate tensile strength of 56,150 lb., were butUwehi<'<I and 
pulled with the following results: 

Test No. Manner of Failure TJ>. j ( , r <? ent 

1 % in P^tc and % in weld 51,000 <1 

2 Tn plate just back of weld 2,000 iKJ 

3 " " " " " " 53,400 i>5 

4 " " " r > 2f(m) {M 

5 " " " " " " 4G,ioo Kr> 

6 " " " (i " " 51,900 c,;i 

On six samples of spot- welded single lap-joint sheets of 14 
gage steel 3 in wide welded with a V 10 in. spot, ihV ii 
at which the welds pulled out, was 4480 lb. " 



398 ELECTRIC WELDING 

The ultimate tensile strength of a piece of plate of 14 gage, 
was 64,500 per sq. in. The ultimate shearing load per weld 
(two spots with an area of 0.0742 sq. in. each) averaged 8942 
Ib. Approximate total welded area, 0.1484 sq. in. This gives 
an ultimate shearing strength for 1 sq. in. of weld, of about 
60,200 Ib. On steel % in. thick and 2 in. wide, welded with 
a spot having an area, measured with a planimeter, of 0.476 
sq. in., the failure under pull was at 34,650 Ib. Examination 
of the welds showed them to be under both a tensile and a 
shearing action. A piece of the same steel tested for ultimate 
strength, failed at 66?800 Ib. per sq. in. This shows that the 
weld was stronger than the original metal. 

The final conclusions drawn by Mr. Hughes from his tests, 
are that, in general, the ultimate tensile strength of a properly 
made butt- or spot-weld, is about 93 per cent of that of the 
parent metal, and the ultimate shearing strength of a properly 
made butt- or spot-weld is also about 93 per cent. 

ELEMENTARY ELECTRICAL INFORMATION 

What is a Volt? This is a term used to represent the pres- 
sure of electrical energy. In steam we would say a boiler 
maintains a pressure of 100 pounds. This term relates to pres- 
sure only regardless of quantity, just as the steam pressure 
of a boiler has nothing to do with its capacity. 

What is an Ampere? This term is used to represent the 
quantity of current. In the case of steam or water we speak 
of carrying capacity of a pipe in cubic feet, while in electricity 
the carrying capacity of a wire is given in amperes. 

What is a Watt? This is the electrical unit of power and 
equals volts X amperes. One mechanical horsepower is the 
equivalent of 746 watts. 

What is a Kilowatt or kw.? 1000 watts, kilo merely in- 
dicating 1000. It is the most commonly used electrical unit 
of power and one kilowatt of electrical energy is equivalent 
to one and one-third mechanical horsepower. 

What is a Kilowatt Hour or kw.-hr.? This is the electrical 
equivalent of mechanical work, which would be stated in the 
latter in. 8 terms of horsepower hour. It means the consumption 
of 1000 watts of electrical energy steadily for one hour or any 
equivalent thereof (such as 5000 watts for 12 minutes) and 



MAKING PROPER RATES FOR ELECTRIC WELDING 399 

is the unit employed by all power companies in selling electric 
power, their charges being based on a certain rate per kw.-hr. 
consumed. 

What is kvB,.? This means Kilovolt amperes or volts X 
amperes-KlOOO. This term is used only in alternating current 
practice and is used to represent the apparent load on a 
generator. In any inductive apparatus, such as a motor or 
welder, a counter current is set up within the apparatus itself, 
which is opposite in direction to and always opposes the main 
current entering the apparatus. This makes it necessary for 
the generator to produce not only amperes enough to operate 
the motor or welder but also enough in addition to overcome 
this opposing current in either of the latter, although the actual 
mechanical power required to run the generator is only that 
to supply watts or electrical energy (voltsX amperes) actually 
consumed in the motor or welder. Hence, the kw. demand 
of a welder represents the actual useful power consumed, for 
which you pay, while the kva. cmand represents the 
vo Its X total number of amperes impressed on the wclder-r-1000, 
to also overcome the induced current set up within, but it is 
the kva. demand that governs the size of wire to be used in 
connecting up the welder. Kw. divided by kva. of any 
machine, represents the power factor of that machine, which 
is usually expressed in per cent. 



INDEX 



,pters for using carbons in metal- 

e electrode holder, *67 

ustable table for spot welding 

Lachines, *2S8, *292 

ustment of die points for spot- 
elding, *284, *297 

welded mill building details, *166 

jrnating-current apparatus, *42, 
*43, *44 

arc welding, 85 

minuin butt-weld, *249, 252 

welded to copper by percussion, 
*274 

erican Institute of Electrical En- 
gineers, paper read be- 
fore, by H. M. Hobart, 
167 

Mining and Metallurgical 

Engineers, paper read 
before the, 223 

erican Machinist, 47, 66, 134, 324, 

39 

erican Boiling Mills Co., elec- 
trodes made by, 13 

Steel and Wire Co., electrodes 
made by, 13 

gage numbers of, 

140 

Welding Society, 214 

imeter charts of operation of Mor- 
on automatic metallic-electrode 

rehling machine, *224 

lount of metal deposited per hour 

n arc welding, 89 

ipere, what is a, 398 

drews, H. H., 212 

W. S., 23 



Angle and plate construction, *94 

for holding carbon, electrode, 69, 

*70 

of electrode in machine welding, 

229 

scarf for arc welding, 60 

Annealing butt welds, 245, *246 

welded tools, 356 

Apparatus used in Bureau of Stand- 
ards arc welding work, *174 

Appearance of tension specimen af- 
ter test, *183 

Application of carbon arc welding, 
77 

"Application of Electric Welding 
to Ship Construction, ; 7 paper by 
Jasper Cox on, 168 

Arc and fusion characteristics, 52 

, carbon, characteristics of, *70 

control, 51 
exercise, *52 

on Morton machine, 225 

formation, 50 

-fused metal, formation of blocks 

of, *175, 176 
, xnacrostructure of, 184, *185, 

*186, *187 

, tests of, by Bureau of Stand- 
ards, 189 
} f by Wirt-Jones, 189 

steel, change in nitrogen of, upon 

heating, 209 

, metallography of, 19 1 

, mierostructure of, 192, *193, 

*194, *196, *198, *199, 
*200, *202, *204, *206, 
*207, *208 
, physical properties of, 171 

401 



402 



INDEX 



Arc steel, summary of results of the 
study of the metallography 
of, 212 

length for carbon-electrode work, 

71 
for various currents when 

using carbon-electrodes, 71 
in metallic-electrode welding, 

82 

maintenance, 50 

manipulation, 49 

in carbon-electrode welding, 

69 

, polarity of, in welding, 53 
, short and long, deposits, *55 
t welding, "*54 

stability, 54 

weld inspections, 63, 96, 103 

welding, automatic, 214, *217, 

*218, *230, *236 

circuits as first used, *3 

equipment, 9 

high-speed tool tips, 162, *164 

jobs, examples of, 127, *130, 

*133, *137, *138, *139, 
*140, *141, *142, *146, 
*147, *148, *149, *153, 
*154, *155, *156, *157, 
*15S, 159, 160, 161, 163, 
164, 166 

machine, a semi-automatic, 

223, *230 

Arc Welding Machine Co., The, 40 

Co. J s constan t-current 

closed circuit system, 
40 

electrode holder, *16, 

*17 

procedure, 81 

set, the G. E., *28 

, speed of, 167 

y 1 by machine, 220, 221, 

222, 233, 238 

terms and symbols, 109 

Arcwell Corporation, 43 

outfit for a-c current, *43 

Armature shaft built up, *153 



Arsem furnace, 208 

Automatic arc welding, 214, *217, 

*218, *230, *236 
Automatic Arc Welding Co., 223 
Automatic arc-welding head, 215, 

*217, *218 
machine, work done by, 

219 

butt-welding machines, *244, 

*245 

chain making machine, *269 

hog-riiig mash welding machine, 

*305, *306 

Automatic Machine Co., 268 
Automatic Pulley spot-welding ma- 
chine, *301 

spot-welder for channels, *300 
Automobile body spot-welding ma- 
chine with suspended head, 
*294 

muffler tubes, seam welded, *372 

rim butt-welding work, 252, *255, 

*259 

Axle housings repaired, *156 
, worn, built up, *160 

B 

Back-step arc welding, 84 
Balancer-type arc welding set, *28 
Band saw welding, *251, 252 
Bench type of spot-welding machine, 

*24S 

Bernardos process, the, 1, 2, *3 
Blow-pipe, electric, the, 1, *2 
Body, automobile, spot-welding ma- 
chine with suspended head, *294 
Boiler tube arc welding, *142, 14.3 

rolling machine, simplest 

form of, *331 
welding with the arc, *89 

tubes, leaks in, 333 

, ready for flash-welding, *329 

Bolt holes, filling, 160 
Booth, the welding, 48 
Bouchayer's spot-welding apparatus, 

*6, 7 
Box, spot-welding a sheet steel, *2S3 



INDEX 



403 



Brass, butt-welding, 267 

seam welding, 366 

Bronze, welding with, carbon arc, 

76 

Bucket welding jig, *375 
Building up a surface with carbon 
arc, *72 

round work, speed of, 223 

worn shafts and axles, *153, 

*160 
Built-up carbon arc weld, section 

through a, *73, *75 
Bureau of Standards, study of arc- 
fused steel at, 171 

, tests on arc-fused steel at, 

191 

Burning, lead, outfit, *45, 46 
Butt weld (arc), definition of, 110 

, boiler tube ends prepared for, 

*327 

-welding attachment for spot- 

welding machine, *286 

boiler tubes, 336 

- device, first practical, *4 

end rings, *266 

jobs, examples of, 247, *249, 

*250, *251, *255, *265, *266, 
*267, *268 

machine, principal parts of, *240 
work clamps, *242, *243, 

*257 

machines, *345, *347, *348, *351 
and work, 239, *240, *241, 

*244, *245, *246, *251, 
*254, *256, *257, *259, 
*261, *262, *263, *264, 
*267, *268 

patents, 4 

pip e > cos t and consumption of, 

258 

rod up to % in. dia., cost and 

current consumption of, 248 

stock up to 2 in. dia., cost and 

current consumption of, 263 
welds, metallic electrode, data 

on, 32 
, strength of resistance, 394 



Cable, size of, for arc welding work, 

18 

Cain, J. B., 177, 178 
Cam-operated butt-welding machine, 

*244, *245 
Can seams, line-welding, *30S 

welding jig, *374 
Car axle enlarged, *160 

equipment, electric, maintenance 

of, 150 
Carbon are, characteristics of, *70 

, cuts, examples of, *77 

spot-welding, *5, *7 

welding, *15 

} application of, 77 

, filler used for, 68 

electrode apparatus, original, *3 

arc seam-welding machine, 

*236, 237 

. . -welding and cutting 1 , 66 

current used with, 66, 68, 71, 

74, 78, 80 

cutting speeds, 31 

process, 10 

, size of, 10, 68 
Cases, motor, reclaimed, *154 
Cast iron, rate of cutting, with car- 
bon arc, 79 

, welds, strength of, 131 

Caulking weld (arc), definition <>i", 

116 

Chain machine, automatic, *269 
Challenge Machinery Co., 288 
Change in nitrogen content upon 

heating arc-fused steel, 209 
Channel iron spot-welding* nuu'h'mo, 

automatic, *300 

Characteristic appearance of tension 
specimen after test, *183 

"needles 77 or " plates ' ' in ai <- 

fused steel, 195, *196, *1S')H, 
*199, *200, *202, *204, *20<>, 
*207, *208 

structure of electrolytic iron, 

*199 



404 



INDEX 



Characteristics of are and fusion, 52 

carbon arc, *70 

the metallic arc weld, factors 

that determine the, 97 

, thermal, of arc-fused iron, 210, 
*211 

Chemical analyses of are deposited 
specimens, 105 

Chemical and Metallurgical Engi- 
neering, 171, 396 

Chemical composition of metallic 
electrodes, effects of the, 104 

Chicago, Rock Island and Pacific 
railroad arc welding work, 84 

Chubb, L. W., 269 

Circuit, schematic welding, *10 

Circular arc welding, automatic, 
*217 

Clamp for butt-welding pipe, *257 

heavy, flat, butt-welding 

work, *243 

tool welding, *346 

, foot-operated, for butt-welding 
work, *242 

j hand-operated, for butt-welding 
work, *242 

toggle lever, for butt-welding 

round stock, *242 

Clamping distance, effect of, on 
time and energy demand, 385 

jaws for boiler tube work, *337 
Clamps for work in butt-welding ma- 
chines, *242, *243, *257 

Classes of electric welding, 1 
Close-up of tool-welding machine 
with work in place, *352 

view of left-hand tool-welding 

clamp, *346 

Coating for metal electrodes, 176 

Coils, butt-welding pipe, *256 

Collins, E. F., 263 

Combination arc welding symbols, 
118, *119, *120, *121, *122, 
*123, *124, *125, *126 

spot- and line-welding machines, 

307, *308, *309, *310 

t-e weld (arc), definition of, 
117 



Composition of electrodes before 
and after fusion, 177, 
178 

used in Morton machine, 

227, 228, 229 

metallic electrodes, 12 

Welding Committee elec- 
trodes, 107 

Comstock, G-. F., reference to, 197 
Concave weld (arc), definition of, 

118 

Condenser, arc welded, *138 
Connections for G. E. constant-en- 
ergy, constant-are set, *30 
Constant-current closed-circuit weld- 
ing outfit, 40 

Contraction of deposited metal in 
arc welding, 58, *59 

and expansion of parent metal in 

arc welding, 57, *59 
Control of arc direction exercise, *52 
travel, 51 

panel for balancer set, *29, *30 
Controlling the arc on Morton ma- 
chine, 225 

Convenient setting of machine for 
spot-welding sheet metal work, 
*295 

Copper butt-welding, 263 

-welds, *249, 252 

jaws for boiler tube work, *337 
holding large heads and 

small shanks, *350 

welding various sizes of 

tools, *349 

welded to aluminum by percus- 

sion, *274 

, welding, with carbon arc, 76 
Correct welding posture, *49 
Cost of arc welding, 90 

in railroad work, 144 

butt- and mash-welding, vari- 
ous sizes, 362 

butt-welding work, 248, 258, 

263 

machine and hand arc-welding 

compared, 221, 222 
metallic electrode welding, 32 



INDEX 



405 



Cost of percussive welds, 272 

pod welds, 147 

repairs in welding flues, 336 

seam welding, 378 

spot-welds, 321 

welding boiler tubes, 335 

Cox, H. Jasper, 168 
Crane wheels, repaired, *221 
Crank forging weld, "*250, 252 
Crankshaft, are welding a 6-ton, 

*161, 162, *163 
Cross-current spot-welding machine, 

*302, *303 
Cross-overs, repaired manganese 

steel, *147 

Current action in a Taylor spot- 
welding machine, *304 

and electrode diameter, relation 

of, *13, 14 

consumption for butt- and mash- 

welding various sizes, 

362 
butt-welding, 248, 258, 

263 

welding 6 -in. seam, 378 

in carbon are cutting, 80 

density of electrode, 61 

for given cases of arc welding, 

169 

required for metallic electrode 

welding, 32 

percussive welds, *273 

ship plate spot- weld ing, 

311, 315, 317, 318, 319 
spot-welds, 321 

used for automatic arc welding, 

220, 221, 222, 223, 228, 
232, 238, 

cutting with the carbon 

arc, 78, 80 

various sizes of carbon- 
electrodes, 68 

in Bureau of Standards tests, 

176 

butt-welding, 240, 243, 

247, 248, 255, 258, 259, 
560, 261, 262, 263 



Current used for carbon electrode 

process, 11 
metallic electrode process, 

11 

values for plates of different 

thickness, 14 

variation, effect of, on strength 

of arc weld, 102 

Currie, H. A., 143 

Curves showing thermal characteris- 
tics of arc-fused iron, *211 

Cutting speeds with carbon elec- 
trodes, 31 

with the carbon are, 77 

. y current used in, 78, 

80 

Cutting-off machine for boiler tubes, 
*325 

Cuts made with the carbon arc, ex- 
amples of, *77 

Cylinder, locomotive, welding with 
the arc, 144 

Cylinders, Liberty, butt-welding 
valve elbows on, *268 



D 



Dangerous light rays, 23 

Data for metallic electrode butt and 

lap welds, 32 
DC Benardo spot-welding apparatus, 

the, *5, 7 
Decimal equivalents of an inch for 

millimeters, B. S. and Birming- 
ham wire gages, 323 
Demand, maximum, in resistance 

welding, 387 
de Mcritens, 1 
Deposit obtained with short and 

long arc, *55 

per hour, arc- welding, 89, 146 
, theory of electrode, 223 
Deposited metal, contraction of, in 

arc welding, 58, *59 
Deposits of short and long ares, 

*102, *103 
Design of arc welded joints, 90 



406 



INDEX 



Details of percussive welding ma- 
chine and wiring diagram, 
*271 

rotor welding machine, *265 

seam welding roller head, 

*368 

standard spot-welding ma- 
chines, 278, *279 

Diagram of control of feed motor 
for automatic arc- welding 
machine, *219 

flange seam welding opera- 
tion, *380 

Die-points for heavy spot -welding, 
314 

spot-welding machines, 288, 

*289, *290, *291, *297, 
*304 

Different makes of are welding sets, 
28 

Direction of arc travel, 51 

Double bevel, definition of, as ap- 
plied to edge finish, 114 

"V, " definition of, as applied to 
edge finish, 113 

Drill blanks just welded, *349 

Drills, Stellite tipped, *34S 

Driving wheel welding, *141, 143 

Duplex spot-welding- machine with 
6-ft. throat depth, *316 

Dynamotor, plastic arc, welding set, 
35, *36 



Edge finish, 112, 113, 114 

Edges, flanged, welded with carbon 

arc, *75, 76 

Effect of clamping distance on 
time and energy demand, 
385 

pronounced heating upon the 

structure of arc-fused iron, 
*206 7 *207, *208 
Effects of the chemical composition 

of metallic are electrodes, 104 
Electric Arc Cutting and Welding 
Co., 44 . 



Electric arc, heat of the, 9 

and oil heating of boiler tubes 

compared, 335 
- " blow-pipe," the, *2 

car equipment maintenance, 150 
Electric Railway Journal, 150 
Electric seam welding, resistance, 

365 

welded ship, 134 

welding, classes of, 1 
Electric Welding Co. of America, 

building for the, 164 
Electric welding of high-speed steel 

and Stellite in tool manufacture, 

343 

Electrical inspection of welds, 98 
Electrical World, 382 
Electrically welded mill building, 

164 

Electrode, angle of, in machine weld- 
ing, 229 

, carbon, original apparatus, 2, *3 
, , size of, 68 

current density, 61 

deposit, theory of, 223 

diameter versus are current, *13 

diameters for welding steel plate, 

101 

holder, a simple form of, *16 
, special form, *16,.*17 

material, analysis of, used in 

Morton machine, 227, 228, 229 
, metallic, original apparatus, 2, *3 
, , speed of welding with, 32 
, size of for arc welding, British 

practise, 169 

wire, best, to use in arc-welding 

machine, 231 

Electrodes before and after fusion, 
composition of, 177, 178 

, composition of Welding Commit- 
tee, 107 

, fusion of, 50 

, graphite see Carbon 

, hardness of, 180, 181 

, metallic, composition of, 12 

, , made by various firms, 13 

, selection of, 12 



INDEX 



407 



Electrodes, size of, 13, 14 
, tensile properties of, 179, ISO, 
181 

used for carbon arc welding, 66, 

*67, 68 
Electro-percussive welding, 269 

machine, *270, *271, 1272 

Elementary electrical information, 

398 

End, strip, welding jig, *376 
Energy consumption of resistance 

welding for commercial grades of 

sheet iron, 384 
Escholz, O. H., 47, 66, 96 
Etching fluid, 55 

solution used by Bureau of 

Standards for steel, 185, 186, 

187, 193, 194, 196, 198, 199, 

200, 202, 204, 206, 207, 208 

Equipment, a welder 's, 64 

Examples of arc welding jobs, 127 

*130, *183, *137, 

"138, *139, *140, 

*141, *142, *146, 

*147, *148, *149, 

*153, *154, *155, 

*156, *157, *158, 

*159, *160, *161, 

*163, *164, *166 

W0 rk ; *S7, *88, *89 

butt-welding jobs, 247, *249 

*250, *251, *255, *265, 
*266, *267, *26S 

seam welding, *371, *372, 

-374, *375, *380 

welded ship parts, *137 

Exercises for the beginner in arc 

welding, 58, *59 
expansion and contraction of parent 

metal in arc welding, 57, *59 
Eye protection in iron welding op- 
erations, 23 



Face masks and shields, *15, *18, 

*19 
Factors that determine degree ef 

fusion, 64 



Federal butt-welding machines, 261, 

*262, *263, *268 
Federal Machine and Welder Co., 

261, 297 
Federal spot-welding machines, *296, 

297, *299, *300, *301 
water-cooled die points, *297, 

*29S 
Feed control diagram of arc welding 

machine, *219 
Ferride Electric Welding Wire Co., 

electrodes made by, 13 
Fillet weld (arc), definition of, 111 
Filler material for carbon arc weld- 
ing, 68 

rods, fused ends of, used in car- 

bon arc welding, *74 
Filling in bolt holes, 160 

sequence in arc welding, *83, 

*84, *85 

Firebox sheet work, *95 
Flange, repair of electric car wheel, 

*157, *158 

scam welding, 374, *377, *380 
_ ^ diagram of operation of, 

*380 

Flanged- edges welded with carbon 
arc, *75, 76 

seam welding with carbon arc, 

*75, 76 

Flash-welding boiler tubes, 336, 338 
Flat position defined as applied to 

ship work, *114, 115 
Flue ends just beginning to heat, 

*340 

almost hot enough for weld- 
ing, *341 

prepared for flash-weld, *329 

, rolling out upset metal on, 

*341 

parts in machine ready for weld- 

ing, *340 

welding (are), *142, 143 

machine, close-up of, showing 

inside mandrel, *339 

, pressure required for, 337 

with the arc, *89 

work, machine for, 337 



408 



INDEX 



Flues, cutting off boiler, *325 
, leaks in welded, 333 
Flush weld (arc), definition of, 118 
Flux for flue welding, using a, 330 

used for seam welding, 366 
Forge, the "water-pail," 1, 3 
Form of points for spot-welding, 

*289, *290, *291, *297, *29S, *304 
Formation of arc, 50 
Fractures of test specimen of arc 

deposited plates, *105 
Frame welding, locomotive, *89, 

*139, *140 

e ' Free distance, ' ' meaning of, 63 
reduction caused by contrac- 
tion, *59 
1 i Freezing ' ' of electrodes, meaning 

of, 50, 64 
Fused ends of filler rods used in 

carbon arc welding, *74 
Fusion and arc characteristics, 52 
, factors that determine degree of, 
64 

of electrodes, 50 

parent metal and four layers 

of carbon, arc deposit, *75 
, poor and good, from arc, *60 

G 

Galvanized iron, welding, 277, *286 
Gear-case repair, *155 

cases with patches welded on, 

*159 

, split, made solid, *160 
General Electric arc- welding gen- 
erator direct con- 
nected to motor, 
*152 

set, *28 

butt-welding machine for 

rotor work, *264, *265, 
*266, *267 

Co., 17, 28, 46, 151, 154, 214, 

237, 307, 308, 319 

portable are-welding outfit, 

151 

General Electric Review, 21, 23, 263, 
311 



General Electric space-block spot- 
welding machine, *307 

features of microstructure of arc- 
fused steel, 142 

" George Washington, 7 ' repair of 
the, *130 

German ships, extent of damage to 
seized, 128 

, repaired, 127 

Gibb Instrument Co., 42 

Glass, qualities of various kinds- of, 
25 

Good and bad arc welds, *100 

Graphite electrodes sec Carbon 

Groesbeek, Edward, 171 

Grooved tool parts to facilitate weld- 
ing, *364 

Guards, spot-welding 12 gage iron, 
*287 

H 

Haas, Lucien, 290 

Ham, J. M., 21 

Hand shield, using a, *"15 

shields for arc welders, *15, *19 
Hardness of electrodes, 180, 181 
Harrnatta spot-welding process, prin- 
ciple of the, *7 

Harness rings, welding, *245 
Hartz type boiler tube rolling ma- 
chine, *332 

Heat conductivity and capacity in 
arc welding, 57 

of the electric arc, 9 

treatment of are welds, 103 
Heating arc-fused steel changes 

nitrogen content, 209 

, effect of, on structure of arc- 
fused iron, *206, *207, *208 

Heavy-duty spot-welding machine, 
*283, *292, *303, *312, *316, 
*318 

experimental spot-welding ma- 

chine, *318, 319 
Herbert Mfg. Co., 296 
High carbon steel welds, strength of, 

396 



INDEX 



409 



High-speed steel, welding, 343 

to low-carbon steel, welding, 344 

tool tips, arc-welding, 162, *164 
Hobart, H. M., 167, 189, 223, 390 
Hoe blades, welding, to shanks, 

*284 
Holder, electrode, simple form of 

*16 
-,-, special form of, *16, *17 

for carbon-electrode, *67 

metallic-electrode, *67 

, the electrode, 48 

Holding stock of unequal size for 

butt-welding, *350 
Holes, filling bolt, 160 
, strength of spot-welded, 392, 

*393 

Horizontal position defined as ap- 
plied to ship work, *114, 115 
Housing, repaired 5-ton roll, 147, 

*14S 

, welded rear axle, *222 
Houston Ice Co., crankshaft repair 

for, 162 
How horn and welding points may 

be set for spot welding, *284, 

*297 

the metal edges of a tank are 

are welded, 237 
Hub, welded automobile, *221 
Hughes, G. A., 397 



Inclusions in arc-fused steel, ' ' metal- 
lic-globule/' *194, 195 
Insert tool welding, *355, *357 
Inspection of are welds, 63, 96, 103 



Jacob, W., 263 

Jaws and work arranged for a mnsh 

weld, *361 
for boiler tube work, *337 

holding two sizes of stock, 

*350 

tool welding, *346, *349, *350, 

*354, *355, *356, *357 



Jessop, E. P., 133 

Jigs for holding seam welding work, 
372, *373, *374, *375, *376, *380 
Joints arc welded, design of, 90 
, stresses in are welded, 92, *93 
Jordan, Louis, 171 



Karcher, A. A., 288 

Kent, William, report on butt-welds 
by, 394 

Kerosene, use of, in inspection, 63, 
98 

Kilowatt-hour, what is a, 398 

, what is a, 398 

Kind of machine to use for welding 
flues, 337 

King face masks, *15, *1S 

Optical Co., Julius, IS 

Kleinschmidt spot-welding appara- 
tus, the, *5, 7 

Kva., what is, 399 



La Grange-Hoho process, the, 1, 3 
Lap weld (arc), definition of, 110 
Lamp shades, mash- weld ing, *285 
Lap seam welding machines, 368 

-welds, metallic electrode, data 

on, 32 

Lathe tool, welded and finished, *354 
Layers of filling material in carbon 

arc welding, *73, *74, *75 
Lead-burning outfit, G. E., *45, 46 
, welding, with carbon electrode, 

76 

Leaks in welded boiler tubes, 333 
Lloyd's Register, 135 
Liberty motor cylinders, butt-weld- 
ing valve elbows on, 268 
Light manufacturing type of spot 

welding machine, *281 

rays, dangerous, 23 
Lincoln Electric Co., 21, 37, 81 

welding set, the, 36, *37 
Line-welding can seams, *308 
Lining up large crankshaft for arc 

welding, *163 



410 



INDEX 



Load factor in resistance welding, 
386 

tests of all- welded mill building, 

165 

"Loeked-in" stresses, result of, 62 
Locomotive arc welding work, 140 

frame welding, *89, *139, *140 
Long and short are deposits, *55 
. welding are, *54 

Lorain machine for spot-welding 
electric rail bonds, *320, 321 

Lorain Steel Co., 321 

Lunkenheimer laboratory tests of 
spot welds, 391 

M 

MacBean, T. Leonard, 164 

Machine for flange-seam welding, 
377 

, kind of, to use for flue welding, 
337 

Machines for resistance butt weld- 
ing, 239, *240, 241, *244, *245, 
*246, *251, *254, *256, *257, *259, 
*261, *262, *263, *264, *267, *268 

Macrostructure of arc -fused metal, 
184, *185, *186, *187 

Maintenance of are, 50 

electric car equipment, 150 

Making a i ' mash ' ' insert weld, *359 

proper power rates, 382 
Mandrels used in flue welding, 330, 

331, 333, *334, *339 
Manganese steel cross-overs, re- 
paired, 147 
Manipulation of are, 49 

the are in metallic electrode 

welding, 82 
Martensite structure in are-fused 

steel, *204 
Mash welding, 284, *285, 306, *319 

machines, *358, *359, *360 

Mask, using a, in arc welding, *15 
Masks, King, for are welding, *15, 

*18 

Maximum demand in resistance 
welding, 387 



Mechanical properties of arc-fused 
metal deposited at right 
angles to length of 
specimen, 184 

twelve good arc welds, 173 

twelve inferior are welds, 

173 

Melting steel in nitrogen under 
pressure, 212 

Meriea, P. D., 197 

Merits of electric and oil heating of 
boiler tubes, 335 

Metallic are welding, *15 

electrode apparatus, original, 2, 

*3 

process, 10, 11 

speed of welding with, 32 

' ' Metallic-globule ' ' inclusions in 
are-fused steel, *194, 195 

Metallography of arc-fused steel, 
191 

Metals, non-ferrous, welding with 
carbon are, 76 

Methods of welding boiler tubes, the 
three, 328 

, the three, of welding boiler tubes 
compared, 336 

Microphotograplis of specimens of 
are deposited metal, *106 

Microscopic evidence of unsound- 
ness of are-fused metal, 193 

Microstrueture of arc-fused steel, 
192, *193, *194, *196, *198, *199, 
*200, *202, *204, *207, *208 

Mill building, electrically welded, 
164 

-, welded parts of, *166 

Miller, S. W., 197, 201 

Morton, Harry D., 223 

semi-automatic metallic-electrode 

are-welding machine, *230 
Motor cases reclaimed, *154 
Muffler tube welding jig, *373 

tubes, seam welded, *372 

N 

1 ' Needles ? ' in arc-fused metal, 195, 
*19(J, *198 



INDEX 



411 



New York Central railroad are weld- 
ing work, 143 

Nitrates probably cause of plates in 
fusion welds, 197 

Nitride plates, persistence of, 208 

, two types of, *199 

Nitrogen content arid current den- 
sity, relation of, 178, 179 

Non-ferrous metals, welding, with 
carbon are, 76 

O 

Oesterreieher, S. I., 382 
Oil and electric heating of boiler 
tubes compared, 335 

stove burner tubes before and 

after seam welding, *371 
Oscillograph chart of percussive 
welds on 18 gage aluminum wire, 
273 

Ortou, J. S., 104 
Outfit, selecting a welding, 21 
Outfits, welding, types of, 21 
Overhead position defined as applied 
to ship work, *114, 115 

scam welding, 62 

Overlap and penetration studies, 

*56, 57 
1 'Overlap, 37 meaning of, 63 



Page Woven Wire Co., electrodes 
made by, 13 

Panel control for balancer set, *29, 
*30 

Parent metal in arc welding, ex- 
pansion and contraction of, 57, 
*59 

' ' Parent metal, ' ' meaning of, 03 

Payne, O. A., 108 

Pearlite islands in arc-fused steel, 
*198 

Pedestal jaw, built-up, *139 

Penetration and overlap studies, *54, 
57 

, current required for proper, 57 

' * Penetration, ' ' meaning of, 63 . 



Pennington, H. B., 84 
Percussive welding, 269 

, the possibilities of, 274 

Physical characteristics of plates 
tested, 104 

properties of arc-fused steel, 171 
Piloted cup, machine welded, *227, 

*228, *229 
Pinion Llank weld, *250, 252 

pod, finished welded, *148 
Pipe, cost and current consumption 

for butt-welding, 258 

heading, *95 

, spot welding galvanized iron, 
*286 

welding, 255 

Plastic arc dynamotor set, 35, *36 

welding sets, *33, *36 

Plate and angle construction, *94 

thickness versus arc current, *13 
"Plates" in arc-fused metal, 195, 

*19G, *198 
Plates, nitride, two types of, *199 

probably due to nitrates, 197 

remain long after annealing of 

arc-fused metal, 208 
Plug weld (arc), definition of, 111 
Plugged plates, strength of, 392, 

*393 
' t Poeohontas,' ' repair of the, 132, 

*133 

Pods, building up roll, *147, *148 
Points for spot-welding 1 work, 288, 

*289, *290, *291, *21>7, *29S, *3()4 
Polarity for carbon arc work, 70 

in are welding, 53 

carbon electrode process, 11 

Portable arc welding sot, *37, *38, 
*39, *42, *43, *44, 45 

butt-welding machines, 247, *257 

spot-welding machines, *292, 

*293 

machine with 27-in. throat 

depth, *312 
Position, correct, for using carbon 

are and filler rod, *<>9 
Positions of the universal spot-weld- 
ing points, a few, *297 



412 



INDEX 



Posture and equipment of arc 

welder, *49 
Potts Co., John, electrodes made by, 

13 

Power factor in resistance welding, 
383 

rates, making proper, 382 

required for percussive welds, 

272, *273 

Pressure required for flue welding, 
337 

heavy spot welding, 312, 

313, 317 
Principal parts of a butt-welding 

machine, *240 

Projection allowed in welding boiler 
tubes, 330, *337, *340 

method of welding, *291 
Properties, mechanical, of twelve 

good are welds, 173 
? 9 inferior arc welds, 173 

of are-fused metal deposited at 

right angles to length of speci- 
men, 184 

, tensile, of electrodes, 179, 180 
Protecting the eyes in arc welding, 

23 

Pulley spot-welding machine, auto- 
matic, *301 

Pulleys repaired by arc welding, 
*149, 150 

Q 

Qualities of various kinds of glass, 

25 
Quasi arc welding, 86 

, speed of, 168 

Quasi Arc Weltrode Co., 86 
weltrodes, how to use, 86 

E 

Bail bonds, spot-welding, *320, 321 

ends, built up cupped, 146 
Railroad arc welding work, 145 
Railway Age, 143 

Rate of arc welding, 146 



Rates, making proper power, 382 

Rays, the infra-red, 23 

, ultra-violet, 23 

, visible light, 23 

Reamer, steps in making a large, 
*353 

c t Recession, ' ' meaning of, 63 

' i Re-entrant angle, ' ' meaning of, 63 

Reinforced weld (arc), definition of, 
117 

Relation of are current and electrode 
diameter, *13, 14 

microstrueture to the path of 

rupture in arc fused metal, 
201 

nitrogen content and current 

density, 178, 179 

Removing broken taps, 150 

Repairing crane wheels, 221 

Resistance welding, 4 

, energy consumption of, 384 

machine, 239 

Rims, automobile, butt-welding, 252, 
*255, *259 

Ring welded to core with arc weld- 
ing machine, *232 

Rivets in a ship, number of, 136 

Rods, strength of mash-welded, *394 

Roebling's Sons Co., John A., elec- 
trodes made by, 13 

Roll housing, repaired, *148 

Rolling boiler tubes, *331, *332, 
*334, *341 

out upset metal on flue ends, 
*341 

Rotatable head two-spot welding 
machine, 298, *299 

Rotor ring butt-welding work, 263 

Rowdon, Henry S., 171 

Ruder, W. S., reference to, 199, 205, 
208, 209 

Rules, general, for arc welders, 146 

S 

Saw, butt-welding a band, *251, 252 
Scarf angle for arc welding, 60 
"Scarf/' meaning of, 63 



INDEX 



413 



Scarf-weld, boiler tube ends pre- 
pared for, *326 

-welding boiler tubes, 336 
Scarfing machine, a, *326 
Scarfs, typical arc weld, *99 
Schematic welding circuit, *10 
Screens for arc welding, *19 
Seam, automatic arc welded tank, 

*222 

, flange, welding, 374, *377, *3SO 
, flanged, welding with carbon are, 

*75, 76 

welding by the resistance process, 

365 

, current consumption for, 378 

, details of roller head for, 

*36S 

machines, *367, *369, *370, 

*373, *374, *375, *376, 
*377 

, material to use for, 365, 366 

, speed of, with automatic arc 

machine, 222 
Sectional view of carbon are built-up 

weld, *73, *75 

Selecting a welding outfit, 21 
Self -contained portable welding set, 

Lincoln, *37 
Semi-automatic arc-welding machine, 

223, *230 

Shaft, building up a, with an auto- 
matic are welding machine, *218 
, built up motor, *220 
Shafts, worn armature, built up, 

*153 

Shearing strength of butt- and spot- 
welds, 397 
Sheet iron and steel, thickness and 

weight of, 322 

, energy consumption in weld- 
ing, 384 

metal are-welding machine, *236, 

237 

work, convenient set-up for 

spot-welding, *295 

steel box, spot-welding a, *283 
Shell, cup for, welded by machine, 



Shells, motor, repaired, *154, *156 
Shields, hand, for are welders, *15, 

*19 

Ship parts, welded, examples of, 
*137 

plates automatically arc-welded, 

*234, *235 

work, spot-welding machines for, 

311, *312, *316, *318, *319 
Ships, German, names of, 127 
Shops of the Santa Fe K. E., 339 
Short and long arc deposits, *55 

welding arc, *54 

Single bevel, definition of, as ap- 
plied to edge finish, 114 

"V, " definition of, as applied 

to edge finish, 112 
Size of cable for arc welding work, 
18 

carbon-electrode, 68 

electrode for metallic are 

welding of steel plate, 101 

electrodes, 13, 14 

Sizes of die-points for spot-welding, 
*290 

electrodes used in automatic 

arc-welding machines, 220, 
221, 222, 223, 232, 238 

wire to use for connecting up 

different sizes of butt-weld- 
ing machines, 363 
Slavianoff process, the, 1, 2 
Sliding horn spot-welding machine, 

*291 

Slip-bands, 188, 202 
Smith, J. 0., 134 
Society of Naval Architects, 168 
Solutions, etching, for steel, 185, 
186, 187, 193, 194, 190, 198, 199, 
200, 202, 204, 200, 208 
Space-block spot-welding machine, 

*307 

Stability of are, 54 
Special set up of are welding ma- 
chine for building up a 
shaft, *218 

machine for circular arc 

welding, *217 



414 



INDEX 



Speed of are travel, 51 

welding, 90, 167 

automatic arc welding ma- 
chine, 220, 221, 222, 233, 
238 

building up shafts or wheels 

with automatic arc ma- 
chine, 223 

cutting with the carbon arc, 

78, 79, 80 

carbon electrode, 31 

deposit per hour in arc weld- 
ing, 89 

percussive welding, 272, *273 

Quasi- Arc welding, 168 

seam welding with auto- 
matic arc machine, 222 

spot-welding, 321 

welding boiler tubes, 333, 335 

w ith metallic electrode, 32 

Split-gear made solid, *160 

Spokane & Inland Empire R. R., re- 
claimed wheels on, 157 

Spot- and line-welding machines, 
combination, *308, *309, *310 

-welded holes, strength of, 392, 

*393 

material that can be, 277 
Spot-welding apparatus, first forms 

o*, *5, *6, *7, *8 

machines and work, 276, *278, 

*279, *281, *282, *283, 
*284, *285, *286, *287, 
*288, *291, *292, *293, 
*294, *295, *296, *299, 
*300, *301, *302, *303, 
*305, *307, *308, *309, 
*310, *312, *316, *318, 
*319, *320 

, details of standard, 278 

for ship work, 311, *312, 

*316, *318, *319 

patents, *5, *6, *7, *8 

power and cost data, 321 

tests on hoop iron, *390, 391 
Spraragen, William, 167 

Square patch are welding method, 
*85 



Stalls, individual, for arc welders, 
*20 

Steel etching solutions, 185, 186, 
187, 193, 194, 196, 198, 199, 
200, 202, 204, 206, 207, 208 

, melting, in nitrogen under pres- 
sure, 212 

plates, rate of cutting, with the ' 

carbon are, SO 

seam welding, 366 

wire butt-weld, *250, 252 
Stellite insert welding jaws, *357 
, jaws used for welding, *356 
-tipped roughing drills, *348 
, welding, 343 

Steps in the making of a large 

reamer, *353 

Stove parts, spot-welding, using 
swinging bracket support, *288 

pipe dampers, spot welding, *285 
Straight, definition of, as applied to 

edge finish, 113 
Strap weld (arc), definition of a, 

110 
Stratton, Director of the Bureau of 

Standards, 171 
Strength of are deposited plates, 104 

weld, variation of, with 

change of arc current, 
102 

welded joints, 91 

welds, 140 

cast iron welds, 131 

resistance welds, 389 

weld (arc), definition of, 116 

of welded joints, 135 

Stresses in arc welded joints, 92, 
*93 

, result of ' ' locked-in, J ' 62 

Strip welding jig, *376 

Strohmenger-Slaughter process, the, 
1,3 

Structure of are deposited metal, 
*105, *106 

electrolytic iron, character- 
istic, *199 

Studies in overlap and penetration, 



INDEX 



415 



Studs, use of, in are welding, 129, 
*130, *133, 144, 155 

Successful welds, reason for, 138 

Summary of the results of the study 
of the metallography of arc-fused 
steel, 212 

Supervision of arc welders, 145 

Surface, building up a, with the 
carbon arc, *72 , 

Suspended head spot-welding ma- 
chine, 294 

Swinging bracket support for spot- 
welding work, *288, *292 

Swivel head, portable spot-welding 
machine, *293 

Symbols, combination arc welding, 
118, *119, *120, *121, *122, 
*123, *124, *125, *126 

used in arc welding, 109 

T 

"Tack," meaning of, 63 

Tack weld (arc), definition of, 115 

Tank, corrugated steel, welding by 

machine, *23<5, 237 
, how edges of, are welded, 237 

seam, welded straight, *222 
Tanks, arc welded, *137 
Taper of carbon-electrode, (58 
Taps, method of welding broken, to 

remove from hole, *149 
, removing broken taps, 150 
Taylor cross-current spot welding 

process, *8 

spot-welding machines, *3()2, 

*303 

Welder Co., 303" 

Teapot spout, a finish welded, *380 

-: welding jig, *380 

Tee weld (arc), definition of, 112 
Tensile properties of electrodes, 179, 

180, 181 
Tension specimen, appearance of, 

after test, *183 
Terminology, a brief, 63 
Terms, elementary electrical, 398 
Terrell Equipment Co., 296 



Test blocks, formation of, for arc- 
fused metal, *175, 176 

Tests, the Wirt-Joiies, on arc welds, 
189 

Thermal analysis of arc-fused steel, 
210 

characteristics of arc-fused iron, 

210, *211 
Thickness and weight of sheet iron 

and steel, 321, 322 
Thomson butt -weld ing machines, 

*240,-*241, *244, *245, *246, 

*251, *254, *256, *345, *347, 

*348, *351 

Co.'s tests on butt-welds, 395 
S p -k W elcls, 391 

Electric Welding Co., 366, 395 
, Elihu, 4 

foot-, automatic-, and hand-oper- 
ated spot-welding machines, 
280 

seam-welding machines, *367, 

*3C9, *370, *373, *374, *375, 
*376, *377 

spot-welding machines, *226, 

*227, *281, *282, *283', *284, 
*285, *286, *287, *288 

vertical mash welding machines, 

*358, *359, *3GO 

Three-roller boiler tube machine, 
* *332 

Thum, E. E., 396 

Time required to cut with the car- 
bon arc, 78, 79, 80 
Tit or projection method of welding, 

*291 

Topeka shops of the Santa Fe Rail- 
road, 339 

Tool parts arranged for welding, 
*354, *355, *357, *361, 
*364 

, grooving to aid in welding, 

*364 

room butt-welding machine, *261 

welding, the insert method of, 

355 

Tools, butt-welding, *350, *352, *354 
Training arc welders, 47, 145 



416 



INDEX 



Transformer of butt-welding ma- 
chine, 239, *240 
Truscon Steel Co., 397 
Tube rollers, boiler, *331, *332, *334, 
*341 

welding machine with built-on 

rolling device, *334, *339, 
*340, *341 

-welding set for butt -welding 

work, *263 

work, examples of, *SS 

Tubes, boiler, pressure required for 

welding, 337 

, , ready for flash weld, *329 
Tubing automatically arc-welded, 

*233 
Tungsten ring machine are-welded 

to cold rolled core, *232 
T-welding, 252 

Twist-drill blanks just welded, *349 
Two-spot welding machine with ro- 

tatable head, 298, *299 
Typical ammeter charts of operation 
of Morton are welding ma- 
chine, *224 

examples of prepared and fin- 

ished arc welding work, *S7, 
*88, *89 

light spot-welding machine, *278 
Types of welding outfits, 21 

U 

United Traction Co., shop repair 

work of, 150 
Universal spot-welding die-points, 

*296, *297, *298 
Unland, H. L., 214 
Unsoundness of are-fused metal, 

microscopic evidence of, 193 
Usalite crucible, 208 
Using a flux for flue welding, 330 
U. S. Light and Heat Co., 40 
portable a-c, motor- 
generator set, 
*39, 40 



Van Bibber, P. T., 324 



Vertical mash welding machines, 
*358, *359, *360 

position defined as applied to 

ship work, *114, 115 

seam welding, 62 
Volt, what is a, 398 

Voltage, effect of, on arc welds, 169 
Voltex process, the, 2 
Vulcan Iron Works, repair of large 
crankshaft by, 162 



W 

Wagner, 167, 169 

Wanamaker, E., 84 

Warping of parent metal caused by 

deposit contraction, *59 
Water-cooled die-points for spot 

welding, *281, *283, *284, *2S6, 

*288, *291, *296, *297, *298, *302, 

*303 

"Water-pair 7 forge, the, 1, 3 
Watt, what is a, 398 
' * Weaving, ' ' meaning of, 64 

of arc, 52 
Weed, J. M., 311 

Weight of sheet iron and steel, 322 
Welded and riveted joints, *389, 391 

automobile hub stampings, *221 

rear axle housing, *222 
Welder, points for the, to learn, 49 
Welding boiler tubes by the electric 

resistance process, 324 

booth, 48 

Committee electrodes, composi- 

tion of, 107 

the Emergency Fleet Corpor- 
ation, " 90, 104, 107, 109, 
134 

high-speed to low-carbon steel, 

344 

Mild Steel, paper on, 223 

other than round tools, 354 

pipe coiis. *256 

rotor bars to end rings in a 

special butt-welding machine, 
263 

Stellite, 356 



INDEX 



417 



"Welding valve elbows on Liberty 

motor cylinders, *268 
Welds, are, the Wirt-Joncs tests on, 

189 
, good and bad arc, *100 

showing poor and good fusion, 

*60 

, terms and symbols for arc, 109 

' ' Welt, ' ' meaning of, 64 

Weltrodes, composition of, 86 

, sizes of, 87 

Westinghonse Electric and Mfg. Co., 
38, 47, 66, 81, 269 

- single-operator portable welding 
set, *38 

Wheel, car, repairs, *157, *158 

Wilson two-arc "plastic are" weld- 
ing set, *33 

Welder and Metals Co., 33, SI, 

88, 128 

welding and cutting panel, *34 



Winfield butt-welding machines, 
*257, *259, 260, *261 

Electric Welding Machine Co., 

260, 295 

spot-welding machines, *291, 

*292, *293, *294, *295 
Wire to use to connect up seam 

welding machines, 379 
Wiring diagram for percussive weld- 
ing, *271 

Wirt- Jones arc weld tests, 189 
Work clamps for butt-welding ma- 
chines, *242, *243, *257 
Worn and repaired crane wheels, 
*221 

motor shaft built up by auto- 

matic arc welding machine, 

*220 

Z 

Zerncr process, the, 1, *2 
Zeus arc-welding outfit, *42